It depends. If it were to have tons of codes on it, it would probably cost more than if you bought it brand new.
$19.99.
24.99
10-30$
41 at amazon
The ds action reply is around 20 dollars. And so is the gameboy advance one.
You can purchase a Nintendo DSi Action Replay in England for around £20-£30.
What exactly do you mean? It's pretty much the same as the Action Replay DS. Be a little more specific and then I'll try to help you.
25 dollars
the same as any other, 20$
19.99 new used is 10.00
An action replay is 19.00 dollars.