16GB vs 32GB vs 64GB: Which new iPad storage capacity should you get?
http://www.imore.com/2012/03/08/16gb-32gb-64gb-ipad-capacity/
How much content will fit on my iPod or iPhone?
http://support.apple.com/kb/HT1867
How to Sell Your Old iPad http://tinyurl.com/85d69lk
Other sources to sell.
eBay Instant Sell http://instantsale.ebay.com/?search=ipad
Sell and Recycle Used Electronics - Gazelle http://www.gazelle.com/
For instant gratification in selling a used iPhone or iPad, Gazelle’s Gadget Trader, an iOS app, is tough to beat. In seconds it detects the device and reveals how much it is worth in good condition. Tap the Sell This Phone to Gazelle button and the deed is done.
Sell Electronics for Cash - Next Worth http://www.nextworth.com/
Buy My Tronics http://www.buymytronics.com/
Sell Your iPad http://www.sellyourmac.com/mac-product-guides/ipad.html
Totem http://www.hellototem.com/
Cheers, Tom 😉