Is there a website that can give me an average price of used products that are sold online?

Eg) I want to know what the average price of a used ps3 on the internet market.

Sorry, I haven't heard of such a business, there may not be much money in putting that information together.

Watching the going prices on ebay may be as well as you will do.

popular.ebay.com/video-games/playst...