Creation of a website-specific currency system

I am looking for someone with experience developing plugins for the e107 open source CMS. Ideally this would also be someone with experience in developing small scale e-commerce solutions for websites using PayPal's Website Payments Pro. See "Other Requirements" for full description of work required. ## Deliverables Specifically, I want a plugin that would allow visitors to my e107 website to purchase "points" that would be a form of currency tied to my site. The payments would be processed through PayPal's Website Payments Pro credit card processing system. Once payment is processed the user's account would be credited with his chosen number of points. Any user should be able to come back at any time and purchase more points. I know that several full-fledged e-commerce solutions exist already in open source form which is why I consider this a small job. I really just need a very stripped down store that only sells one item and that allows people to buy as many of those item as they like.