Subscribers come from four places: other newsletters recommending you, your own readers referring friends, paid ads, and better signup forms on the traffic you already have.
The tools below cover all four. greetform is owned by 8th Replay, the company behind this site, and is listed with the same facts-only treatment as the others.
At a glance
| Free plan | How it charges | |
|---|---|---|
| SparkLoop | Yes. Free, paid and partner recommendations are included free, with no monthly subscription cost. | Recommendations are free to use; SparkLoop withholds a 20% commission plus a small processing fee on paid payouts. Partner brands pay only for subscribers who meet quality rules. |
| beehiiv Boosts | No. Paid recommendations need the Lite or Pro plan. Free recommendations are available on all beehiiv plans. | Per subscriber, at a price the buyer sets. The buyer is charged only when a subscriber passes verification and engages. $2.20 per subscriber is only an example. |
| ReferralHero | Yes. $0 a month for up to 25 subscribers, with all PRO features and ReferralHero branding. | A flat monthly fee per tier with a member cap. SMS, MMS and Verify are pay-as-you-go. |
| Meta Ads Manager | Not published. | Ads compete in an auction. You set an average daily budget or a fixed budget for the whole campaign. There is no minimum budget. |
| Google Ads | Not published. | You set bidding preferences for what you will spend per click or per number of views. No minimum is published and you can set a maximum bid. |
| OptinMonster | No. There are only paid plans, with a 14-day money-back guarantee. | By campaign impressions, not pageviews, with limits on sites and impressions per plan. Basic covers 1 site and 2,500 impressions. |
| greetform | Yes. $0 forever, with 250 new subscribers a month, 1 publication, 1 survey, 1 form and 3 offers. | A flat monthly fee by plan, with a limit on new subscribers a month. Enterprise is custom. |
Prices and plans change. We checked these figures on October 10, 2026, so confirm them before you buy.
What each one is
SparkLoop
SparkLoop is a newsletter growth platform for paid and free recommendations, partner programs and subscriber referral programs. Growing a newsletter list and earning money by recommending other newsletters.
beehiiv Boosts
A beehiiv tool where newsletters pay partner publishers for each verified new subscriber they recommend. Paying to grow a newsletter's subscriber list through other newsletters.
ReferralHero
ReferralHero is software for referral, affiliate, contest and waitlist programs that can be used to grow an email list. Getting readers to refer others to a newsletter.
Meta Ads Manager
Meta Ads Manager is the tool for buying ads on Facebook, Instagram and other Meta apps, including lead ads that collect sign-ups. Paying to reach new readers and send them to a newsletter sign-up page.
Google Ads
Google Ads is Google's ad platform for showing ads on Search, YouTube, Gmail and other Google places, used to find new newsletter readers. Paying to reach people and send them to a newsletter sign-up page.
OptinMonster
OptinMonster makes popups, slide-ins and other site campaigns that turn visitors into email subscribers. Collecting newsletter sign-ups from website visitors.
greetform
A form that appears after someone subscribes, asks a few questions and shows offers matched to the answers. Asking new subscribers questions and turning answers into offers and leads.
Where to start
Start with what costs nothing. Free recommendations between newsletters of a similar size and a clearer signup form both work before you spend a dollar.
Move to paid growth once you know what a subscriber is worth to you. Paying per subscriber only makes sense when you can say how much each one earns back.
Can I use SparkLoop without paying a monthly fee?
Yes. You can create a publication and make and receive free and paid recommendations with no monthly subscription cost.
What happened to beehiiv Boosts?
Boosts are now called paid recommendations. They live in the Recommendations hub under the Grow tab, and how paid growth works has not changed.
Is there a free plan?
Yes. It is $0 a month for up to 25 subscribers, with all PRO features and ReferralHero branding.
Is there a minimum budget for Meta ads?
No. There is no minimum budget. You can set an average daily budget or a fixed budget for the whole campaign.
Where can Google Ads show?
Google Search, YouTube, Google Play, Discover, Gmail and the Google Display Network.