First determine what the average selling price is currently for the game on Ebay. Figure it costs ~$10 in fees and shipping.
That is the net you'll get for the game. Then check gamestop for trade-in value to see what is the better deal for you.
For ebay you will also need a paypal account to receive the money. Then you list the item as accurately as possible. Ship item as soon as the buyer has actually paid you and you have the money in paypal. (Always pay for tracking and put that tracking info in paypal) Once they receive it and leave you positive feedback, leave positive feedback for them.
Most of the time IF I buy a new game new I get ~$35-40 back through Ebay. I then use that to buy some other used game or just put it back into my bank account. However, if I bought the game used off of Ebay in the first place I can get almost all of my money back. The Key is to sell games as as possible while they are still in demand.







