Apple will buy back your old iPad through the their Reuse and Recycling Program. This program will allow you to exchange your old gadgetry (iPhone, iPad, iPod Touch, Macbooks, and many others) for Apple gift cards. This will not only help you save money to put towards the new iPad, but it also allows you to be green by reducing the number of Apple products ending up in a land fill.
Here are the trade-in values for the iPad 2 (according to TNW.com):
iPad 2 WiFi (16GB) - $205
iPad 2 3G (16GB) - $250
iPad 2 WiFi (32GB) - $245
iPad 2 3G (32GB) - $280
iPad 2 WiFi (64GB) - $275
iPad 2 3G (64GB) - $320
The prices above are for perfectly functioning iPads with no scuffing, engraving, or dead batteries. The iPad must be shipped with a power cord and all of the data wiped clean. Water damage, cracks, and wear all effect the value that Apple will give you.
Another, and arguably one of the best trade-in values, is Amazon's program. They give you a gift card in return for choosing them. This is great if you are a frequent Amazon shopper.
Whether you go with Apple's program or some other, make sure you recycle your old devices. This will not only help your wallet, but the environment as well.
Who would you go with?