GameStop Trade-In Question?

[Treatortrick]

If I trade in a DSi XL and a DS Lite how much would I get off the 3DS

 

[shinetyler]

I have tried that but this is what I do...It is no illegal but it is sketchy. When my xbox goes out of commision. I go to Wal-mart and buy a new one. I ask the person in electronics not to write down the serial code on the reciept ( I usually know the person) Than I go home and do a switch..