Sprint Ebay Dealers

I was recently looking on ebay at some of the ebay stores that sell sprint phones. these stores, with names like sprint depot, mojowireless, and sprint zone, have ridiculously cheap offers like a mogul for $99.99 or even a 755p for $.99 after MIR if you sign up for a new 2-year contract with them. just wondering if anyone out there had ever purchased a phone this way or was familiar with the process they go through. i've read some places that you simply have sprint run a credit check and give them your account number so that they add the phone, as opposed to you giving them all your credit information. any input or experiences you share would be greatly appreciated.