I am wondering about pricing for a side project, but I am unsure if it is worth spending time on getting this setup before launching, when there isn't any guarantee that the project will be sucessful.
If you don't want to invest time into building the billing setup (I assume you mean that), then just see whether you can get to talk to people (e.g. through a waiting list) and then charge money manually. Stripe does pretty much all of your work, even if you add subscriptions manually.
By the 3rd or 4th customer, think about setting up a 'real' system :)
there is no guarantee.
via John C. Maxwell...
try it. see what happens. you won't regret it.