I don't think that a good one of these exists or can easily be made because the difficulty of integrating with third party services. Plus, those third parties m

I don't think that a good one of these exists or can easily be made because the difficulty of integrating with third party services. Plus, those third parties may not look the same for everyone else. This is a category of startup I would call "integration hell." For the most part, I would recommend to avoid these ideas if you're looking at pursuing it. However, it can be fruitful if done correctly - i.e Stripe.