Want to create something like iStock

I have read through this forum and have not found a clear enough answer to the problem that I am having. Here is what I would like to implement  a photo gallery to allow users to download the images after spending the vodes a-la "istock" but since my php skills are 1 on a scale of 10 I have no idea how to do it and the previous threads have not helped enough. The gallery i would like to use is Phoca but I'm willing to use any other that would be easy to implement it on also i am using J! 1.5.7 any help would be greatly appreciated!

Im currently building a vodes spending plugin as 5 months ago I was in the same shoes myself.... I just ask, once I make it available, you help spread love to my site...


Ill let you know when Im done with the plugin