How to develop a site?

[higyu]

How do you find good contents for the domain that I wish to develop?

For example, I'd like to develop PriceCheat(s).com as a coupon service site. I could develop classified or directory listing like application/system but where can I get all those coupon lists and discount offers?

Is there any referential site to look up all the content providers?

Hope this question makes sense to you~

Thanks