The first one I obtained, I remember because I learned a valuable lesson from at the time. It was an iPhone 3G that I was told was a 3GS. I ended up making only $5 on it instead of the $50 I thought I was going to make! It definitely taught me how to tell the difference between the 2 phones, and that you can't always trust people. And the majority I was buying off of Craigslist or friends on Facebook.