ChatGPT answers, unedited

If cheap + subject-line A/B testing is the priority, I’d pick MailerLite.

MailerLite includes email A/B testing—even on its free plan—and specifically supports testing subject lines. MailerLite MailerLite

mailerlite.com

Brevo's A/B testing, including subject-line testing, starts with its $18/month Standard plan. Brevo Help Brevo Help

brevo.com

My recommendation

Start with MailerLite Free. If your list is under 250 people, you can literally get subject-line A/B testing for $0. Once you outgrow it, MailerLite's paid plans start around $12/month. MailerLite

If you tell me roughly how many subscribers you have and how many emails you send per month, I can tell you which plan will be cheapest for your specific list size.

If your main requirement is cheap + subject line A/B testing, I’d shortlist these:

My picks by situation:

• You have <5,000 subscribers and mostly send newsletters: choose MailerLite. It’s usually the best price/features balance and includes A/B testing features. MailerLite
• You just need basic subject-line experiments and a familiar interface: choose Mailchimp. BrandJet AI
• You’re building funnels, sequences, and automations: choose ActiveCampaign. Prospeo

I’d avoid paying for a more complex platform just for subject lines—most teams only need to test:

• Subject line A vs B
• Preview text
• Send time
• Occasionally sender name

For a lean setup, I’d start with MailerLite, then move to ActiveCampaign only when automation becomes the bottleneck. MailerLite Prospeo

If you tell me your subscriber count and whether this is newsletter, ecommerce, or cold outreach, I can narrow it to one choice.

If cheap + subject-line A/B testing is the priority, I’d pick MailerLite.

MailerLite explicitly includes A/B testing—including subject lines—on its free plan. The free tier allows up to 250 subscribers and 2,500 emails/month. www.mailerlite.com

It can also automatically send the winning subject-line version to the remainder of your list after the test. www.mailerlite.com

One important caveat: if your list is larger than 250 people, MailerLite's Comfort plan starts at $12/month, while Brevo's A/B testing starts on its $18/month Standard plan. www.mailerlite.comhelp.brevo.com

My recommendation:

• ≤250 subscribers: MailerLite Free, easily.
• 250–1,000+: MailerLite Comfort is probably the sweet spot.
• Huge contact list but relatively few emails: consider Brevo, since its pricing is based heavily on email volume rather than stored contacts. www.mailerlite.comhelp.brevo.com

If you tell me roughly how many subscribers you have and how many emails you send per month, I can tell you which will actually be cheapest.

If your main requirement is cheap + A/B testing for subject lines, I’d choose MailerLite.

My pick: MailerLite

• A/B testing is available even on the free plan, including subject-line testing. www.mailerlite.comwww.mailerlite.com
• Free plan currently includes 2,500 emails/month (with a 250-subscriber limit on the current pricing page). www.mailerlite.com
• Paid Comfort starts at $12/month and adds more automation and other features. www.mailerlite.comwww.mailerlite.com
• It's particularly attractive if you're building a newsletter or small-business email list and don't need a full CRM.

MailerLite pricing

When I'd pick something else

One important distinction: Brevo's free tier is generous on contacts, but its A/B testing isn't as attractive if A/B subject-line testing is a must-have at the lowest price. MailerLite explicitly includes A/B testing in its free plan. mrreviewai.com

Bottom line: If you tell me roughly how many subscribers you have (or expect) and how many emails you send per month, I can tell you which is actually cheapest for your specific situation.

If cheap + subject-line A/B testing is the priority, I’d choose MailerLite.

My pick: MailerLite

• Free plan: up to 250 subscribers and 2,500 emails/month
• A/B testing is included even on the free plan, including subject lines. www.mailerlite.com
• You can test subject lines, sender names, content, and sending times. www.mailerlite.com
• Paid Comfort starts at $12/month for up to 500 subscribers, with more automation/features. www.mailerlite.com

Runner-up: Brevo

Brevo is also inexpensive, but its A/B testing starts on the $18/month Standard plan, rather than the free tier. help.brevo.com

Bottom line: If you're primarily sending newsletters/campaigns and want to experiment with subject lines without spending much, go with MailerLite. If you tell me roughly how many subscribers you have and how many emails you send/month, I can tell you which plan will actually be cheapest.

If your main requirement is cheap + A/B testing for subject lines, I’d pick MailerLite.

Why MailerLite: its free plan supports up to 250 subscribers and 2,500 emails/month, and includes campaign A/B testing. Their A/B testing specifically lets you test subject lines, and you can run up to five versions of a single element. www.mailerlite.com

MailerLite pricing

One important caveat: if you expect your list to grow substantially, Brevo can become more economical because its pricing is based primarily on email volume rather than contacts. But its A/B testing is on the Standard plan, currently $18/month. www.brevo.com

Brevo pricing

My pick

• Under 250 subscribers: MailerLite Free
• 250–5,000 subscribers: MailerLite is probably the best cheap/simple choice
• Large list + relatively few emails: Consider Brevo
• You mainly care about newsletters + subject-line testing: MailerLite

If you tell me roughly how many subscribers you have and how many emails you send per month, I can tell you which will actually be cheapest for your situation.

If your priority is cheap + subject-line A/B testing, I’d choose MailerLite.

🥇 My pick: MailerLite

MailerLite pricing

MailerLite's free plan includes email A/B testing, with up to 250 subscribers and 2,500 emails/month. Its A/B testing specifically supports testing subject lines, and you can test up to five versions of an element. www.mailerlite.com

Once you outgrow the free tier, the paid Comfort plan starts at $12/month (for up to 500 subscribers on the current pricing). www.mailerlite.com

Brevo is my second choice. Its free plan is generous on contacts, but A/B testing is on the $18/month Standard plan, so it's less attractive if testing is the main thing you care about. help.brevo.com

Bottom line: If you're starting small and want to experiment with subject lines without paying, go with MailerLite.

If you tell me roughly how many subscribers you have and how many emails you send per month, I can tell you which one will be cheapest at your actual scale.

If cheap + subject-line A/B testing is the priority, I’d choose MailerLite.

• Best value: MailerLite — its free plan includes campaign A/B testing, and paid plans start around $12/month. You can specifically A/B test subject lines, with up to 5 versions for a single element. www.mailerlite.com
• If you have a larger contact list: MailerLite is still attractive, but its pricing scales with subscribers. For example, a 2026 comparison puts it around $15/mo at 1,000 contacts and $73/mo at 10,000. www.etropo.com
• Brevo can be cheaper if you send lots of emails to a relatively large contact database because it prices more around email volume than contacts. But I'd pick MailerLite if straightforward email marketing and testing are your main needs. www.mailercloud.com

My pick: MailerLite, especially if you're under ~10k subscribers.

If you tell me roughly how many subscribers you have and how many emails you send per month, I can compare the 3–4 cheapest options and tell you which will actually cost the least.

If your priority is cheap + subject-line A/B testing, I’d pick MailerLite.

• MailerLite: A/B testing is available even on its free plan, including testing subject lines. The current free tier is up to 250 subscribers / 2,500 emails per month; paid plans start around $12/month. www.mailerlite.com
• Brevo: Also good value, especially if you have a large contact list but send relatively few emails. However, subject-line/content A/B testing is on its Standard plan, currently around $18/month before discounts. www.brevo.com
• Mailchimp: I wouldn't choose it if cost is the main concern; you're generally paying more for comparable functionality.

My pick

Small list → MailerLite. You get A/B testing without paying just to unlock it, plus a pretty straightforward editor.

Large list → Brevo. Its pricing is based more on email volume than number of contacts, which can make it substantially cheaper when you have lots of subscribers who don't receive every campaign. www.mailerlite.com

If you tell me roughly how many subscribers you have and how many emails you send per month, I can tell you which one will actually be cheapest for your situation.

If cheap + subject-line A/B testing is the priority, I’d pick MailerLite.

MailerLite is the standout because A/B testing is included even on its free plan, and it specifically supports testing subject lines. Its free tier currently allows 2,500 emails/month; paid plans start around $12/month. www.mailerlite.com

Brevo is worth considering if you expect to need more sophisticated automation, but its A/B testing is on the Standard tier, currently starting at $18/month. help.brevo.com

My recommendation: Start with MailerLite Free. You can test subject lines without paying anything, and upgrade only when your list or automation needs outgrow it.

MailerLite pricing

If you tell me roughly how many subscribers you have and how many emails you send per month, I can tell you which plan/tool will be cheapest for your specific volume.

If cheap + subject-line A/B testing is the priority, I’d choose MailerLite.

My pick: MailerLite

• Free: up to 250 subscribers and 2,500 emails/month
• A/B testing is included even on the free plan, including testing subject lines. www.mailerlite.comwww.mailerlite.com
• Paid plans start around $12/month for 500 subscribers, with more automation and features. www.mailerlite.com
• You can test multiple versions and have MailerLite automatically send the winning version to the remaining audience. www.mailerlite.comwww.mailerlite.com

Runner-up: Brevo — its free plan is generous for contacts, but A/B testing requires the Standard plan, starting around $18/month, so it's less attractive if testing is a must-have on a budget. help.brevo.com

Bottom line: If you're a small list and specifically want to experiment with subject lines without paying much, MailerLite is the better deal.

If you tell me roughly how many subscribers you have and how many emails/month you send, I can tell you which plan will be cheapest.

If your main requirement is cheap + subject-line A/B testing, I’d choose MailerLite.

MailerLite is the standout because A/B testing is included even on its free plan, including subject lines. Its free tier currently allows up to 250 subscribers and 2,500 monthly emails. www.mailerlite.com

Kit is also good if you're primarily running a newsletter: its Creator plan supports two subject-line variants, while testing up to five variants requires Creator Pro. help.kit.com

Brevo is attractive if you have a large contact list because it doesn't charge based on stored contacts, but its A/B testing starts on the Standard plan at $18/month. help.brevo.com

My pick

Start with MailerLite. It's the best fit if you're trying to spend as little as possible while still getting genuine subject-line A/B testing.

MailerLite pricing

If you tell me roughly how many subscribers you have and how many emails you send per month, I can tell you which one will actually be cheapest for your situation.

If cheap + subject-line A/B testing is the priority, I’d pick MailerLite.

MailerLite includes A/B testing even on its free plan, including testing subject lines, and its free tier allows up to 250 subscribers and 2,500 emails/month. www.mailerlite.com

Brevo's A/B testing—including subject lines—is available on Standard, starting at $18/month; its $9 Starter plan doesn't include it. help.brevo.com

So my recommendation: start with MailerLite. You can run subject-line tests for free, then move to its Comfort plan (starting at $12/month) if you outgrow the free tier. www.mailerlite.com

MailerLite pricing

If you tell me roughly how many subscribers you have and how many emails you send/month, I can tell you which tool is cheapest at your actual scale.

If cheap + subject-line A/B testing is the priority, I’d pick Brevo.

My ranking

Why Brevo: its pricing is based largely on emails sent rather than number of contacts, which can be a big advantage if you have a large list but don't email constantly. Its Standard plan includes A/B testing for subject lines and content and starts around $18/month on Brevo's current pricing page. help.brevo.commailchimp.com

Brevo official pricing

Mailchimp is a good alternative if you value ease of use and integrations. It supports subject-line A/B tests and automatically sends the winning version to the remaining audience, but A/B testing is on paid marketing plans, and current Standard pricing starts around $20/month. mailchimp.com

Mailchimp official pricing

Bottom line:

• Small/medium list + want to spend as little as possible → Brevo
• Want the easiest, most established interface → Mailchimp
• Newsletter/creator business → consider Kit

If you tell me roughly how many subscribers you have and how many emails you send per month, I can tell you which one will actually be cheapest for your situation.