That's actually a very nice idea

But it would be even cooler if it would remain free forever instead of the first people to sign up. It's a good idea to make money, though I can't say 100% that it will work. I believe myself to be a fairly good coder and I have the money to have someone build me a website (even a professional company if I wanted it to be THAT good) but I still have yet to figure out an idea on a webpage that could earn me lots of money with the least amount of work.
Good idea though, and I wish you the best of luck.