Nobody here is going to sign up for equity, but that's fine, you probably don't need a co-founder. This forum works best for specific problems: post the actual payment error (the console output and what you clicked), and people will help you fix it for free. Auth and deploy can be separate questions after that.
One pointer, because it's the most common way Stripe breaks in Bolt apps: check where the Stripe secret key lives. If it's in a VITE_ variable or called from a React component, it ends up in the browser and Stripe calls fail (and anyone can read your key). The Checkout Session has to be created server-side, in a Supabase Edge Function for example, with STRIPE_SECRET_KEY stored as a function secret. The frontend only calls that function and redirects to the URL it returns. Also test checkout with the preview opened in its own tab, Stripe Checkout won't load inside the preview iframe.