Looks like its a bit more complicated than that according to the webpage.
Stripe Payments [1]: 2.9% + $0.30
Stripe Billing [2]: 0.5%
Stripe Invoicing [3]: 0.4%
[1] https://stripe.com/pricing
Stripe Payments [1]: 2.9% + $0.30
Stripe Billing [2]: 0.5%
Stripe Invoicing [3]: 0.4%
[1] https://stripe.com/pricing
All in all, we're looking at $0.30 + 3.4% (or 3.3%). This is clearly lower than 30%, except for very inexpensive apps (~$1.29 or less).