The transition to a new generation of consoles isn't exactly the most convenient thing in the world. Firstly you have to fork out money for the new console, and then you have to invest in new controllers, new games and new peripherals. On top of this, this time round we won't be able to play Xbox 360 games on the Xbox One so if you want to play games like Battlefield 4, COD Ghosts or FIFA 14 on the new generation console, you'll have to go out and buy the Xbox One version.
Luckily, Microsoft is making the transition a lot easier and a lot less tight on your wallets. You will be able to 'trade in' your current gen copy of games and in return receive a next gen version. For example, if you have purchased COD Ghosts for the Xbox 360 but want to play it with your buddies when they get it on Xbox One, you'll be able to drastically reduce the cost of the Xbox One version by trading in the Xbox 360 version.
In fact, you'll only have to fork out another $10 to receive a copy of the game on Xbox One.
Unfortunately this deal seems to only be available on Amazon, the Microsoft Store and Best Buy and will probably be exclusive to the US. Currently there doesn't seem to be any similar deal for PlayStation either.