Virtual cash shop

Hello people,

I'm new to web design/scripting and i need some guides/suggestions.
Maybe i should start with some simple newbie questions...but i think i can find them in numerous tutorials around the web.
So i'll just ask about something i lost huge amount of time searching for it.

My project will probably be some sort of browser game, i still haven't started and probably won't until i gather all the info/tutorials i need to support me on my way.

I want to make "virtual item shop".(like the ones you can see in many multiplayer/mmo games now)
So i don't need some "physical carts" that allowes you to sell and ship things around the globe, just plain and simple "buy crystals/coins" or some other virtual cash for real money that they can use for buying other virtual stuff later...aka swords/axes/maces etc.

So, if anyone have some tutorials regarding such stuff or suggestions how to make such thing and implement it, or anything that can help please comment.

Thank you in advance.