Hi @wboone, yes, the way this template works, is when users sign up they are redirected to the Stripe platform and asked to register to Stripe before being signed up on the site. This step can be removed from your workflows if you will, so users can just sign up on your application. However, it will be required anyway to create or log in with existing Stripe account at a certain point, in order to be able to proceed with payments using Stripe.
Regarding the error, please check all your keys in the Stripe plugin settings. They should be different for development vs live version of your app. Your Stripe account has a test vs live toggle as well, which will allow you to get the keys for each mode. Then give it a try again.
Hope it helps.