What's the payment threshold? I assume you're paying 2.9% and $0.30 (or around there) for the transaction. You charge that to the customer but what if their bill is $0.01, are you really going to make them pay $0.32 for $0.01 of usage? How do you expect SaaS providers to communicate that on their pricing page? If they charge $0.01 per request and the end-user makes 100 requests their bill is actually $1.33 which means the actual per-request charge is $0.0133.
Several years ago Stripe offered more favorable pricing for small transactions but it's my understanding that that pricing is no longer available to new Stripe businesses.
If a customer's balance is under $1 at the end of the month, we delay charging them for up to 60 days and send email reminders. If it's still under $1 after 60 days, we charge at least $0.50 and credit the difference (after fees) to their account for future use.
Several years ago Stripe offered more favorable pricing for small transactions but it's my understanding that that pricing is no longer available to new Stripe businesses.