I'm a complete newbie to using online payment systems for web projects, and can't really think of where to start. Let's assume that web system in question needs to generate some income online, and the business idea/functionality is in place, while organizing cash flow is the only unsolved problem.
Points of interest are how the custom developed software interfaces to payment systems, and how the resulting income is available to the owner.
I do understand that there are probably hundreds of systems out there, but to be more specific on which of them suit, I'd have to know how they work, and that's where I don't feel like understanding much.
Thanks in advance.