Go check out the website gazelle*com If you are not familiar with how this website works, it allows consumers to sell their old electronics ? such as cellphones, laptops, mp3 players, digital cameras, camcorders, gaming consoles, GPS devices, and others ? for cash. So what you do is you type in your item that you want to sell, answer a few questions about it's condition, then they will give you an instant quote of what they will pay for the item. What I want to figure out is how do they determine the value of these used items automatically. I know that they have built some type of algorithm to do this. I imagine it goes out an scrapes some type of pricing data for the used items and uses the data to determine the current retail value of the used item. Then I guess they just payout a certain % of the retail value, also adjusting the price according to condition of the item. That's just an idea of what they might be doing. Does anyone have any ideas of what they are doing? Where are collecting their data to determine the value of the used electronics? What kind of mathematical algorithm are they using?