Short answer: beehiiv Boosts (now called paid recommendations) are worth it as a buyer if a newsletter subscriber is worth more than about $4 to you, and usually not worth it as a seller. The sticker price is $1 to $3 per verified subscriber, but once you account for the engagement decay everyone reports on these subscribers, your real cost per reader who is still opening in 90 days lands closer to $4 to $6. On the selling side, publishers on r/beehiiv report verification rates of roughly 23 to 30 percent, which means three quarters of the signups you send earn you nothing.
The conditional matters because Boosts are really two products. Buying subscribers can pencil out if your revenue per subscriber supports it. Selling placements, the arbitrage everyone on YouTube pitches where you run cheap Meta ads and pocket boost payouts, mostly stopped working once verification rates settled in the mid twenties.
Nobody neutral has done this math in public. beehiiv's pages sell Boosts, SparkLoop's pages sell SparkLoop, and Reddit is full of people who feel scammed by both. This guide is the referee: what a subscriber actually costs after verification losses and churn, why your verification rate is probably low, how the beehiiv-versus-SparkLoop pricing fight actually shakes out (the $2,000 per year claim is real but misleading), whether SparkLoop is legit, and when a free cross-promotion beats paying for either. All numbers below are sourced from beehiiv's own documentation, SparkLoop's own help center, and threads from working publishers, linked so you can check them.