This is pretty simple:
Buy the Fable III LCE from Amazon, which comes with a $20 giftcard for a
future game purchase.
Link: http://www.amazon.com/Fable-III-Limited-Collectors-Xbox-360/dp/B002I0H7U6/ref=sr_1_2?ie=UTF8&qid=1288107020&sr=8-2
Immediately click the trade in button to lock in the $75 trade in price,
print out the label, slap it on the box and send it back to Amazon.
Easy peasy.
Worth noting: You have to send the game in within a week so if you have
Prime, play it for a few days, redeem the DLC...easy.
