Hey! Kelly from Stripe here: Just to clarify, there's no additional cost for using Checkout, and Radar is per small per transaction fee (or included free with Stripe if you're just starting out!), not a variable 0.5% fee.
I am no Stripe pricing authority, and have no relation to the company, but I'm pretty sure that is *not* what she said.
She said that Checkout does not have an additional cost on top of transactions fees, not that Tax does not have an additional cost.