Unless your product is a billing system, stop right now and go look at using a third party. Zuora, Stripe, etc all have billing platforms you can use. Trust me

Unless your product is a billing system, stop right now and go look at using a third party. Zuora, Stripe, etc all have billing platforms you can use. Trust me from hard earned experience that billing system seem "easy" but they really aren't. They are very, very hard to get right and if you fuck up you are gonna overcharge, undercharge or god knows what else and piss your customers off. Not only that but you'll be stuck in a loop writing features that work out of the box with third party software. Important ones like the ability to change the price, customize the price for a single account, refund money, export to quickbooks, add new products, offer coupons, offer sales, provide quotes to prospects, etc. You don't want to do this! A third party does all this and more. So yeah. Don't build it! You'll regret doing so! Trust me!