Are there any sites like ebay that you don't need to pay to bid for stuff?

I'm looking for a website that is kind of like ebay or amazon, bbut cheaper. However every site I have come across requires you to buy credits or something in order to bid. Also how can I know if a site like that is legit. One site had really cheap things like iPads for under ten dollars, but I was told that I shouldn't have to pay just to bid and not even win. Right now I'm looking for a cheap Kindle 3G. I just got a NOOK Color and there's nothing wrong with it but for travel I want the 3G but for one thing I just spent most of my money on the NOOK plus if I tried getting a Kindle for full price my mother would not be happy. Any help?