I haven't setup payment processing since around 2002 or 2003, but it sounds like things have improved considerably. Back then, around the only option was Paypal

I haven't setup payment processing since around 2002 or 2003, but it sounds like things have improved considerably. Back then, around the only option was Paypal. To get that to work (in any sort of automated fashion), you had to utilize their API and write your own custom code to process all of the communication with Paylal and your site and your database and to update accordingly (to acknowledge payments, subscriptions, user status change, re-ups, etc). It wasn't as complex as I had feared it was going to be, but it was far from simple and farther from ideal. Especially since they had a habit of changing the API and the automated services over time. I also never liked that you had to kick users out to the Paypal site at some point, to facilitate the payment.