Online Payment System

I am planning to have an online payment system like paypal. But I have no idea about how it works. I need serious proposals and explanation documents from coders who did similar work before. I need detailed technical explanation and business explanation like:what is the estimate operating cost...etc.. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request. 3) Complete ownership and distribution copyrights to all work purchased. ## Platform web, iis