It takes 5 minutes to find out what gazelle.com will give you for it and then I did a search (for my iPad 1 16GB+3G) on ebay for what these were selling for (by searching and checking the "sold items" box). In the case of my iPad 1 it was more than I could get otherwise, but, not sure about iPad 2's.
That would make sense as my receipt for my new iPad Mini states $200 Mastercard Charge for payment (plus my other payment), there's no indication I've used a target gift card. In fact, the $25 Target gift card I got with the iPad Mini purchase has only a bar code on the back, it is entirely different than the card I got from the mobile guy for the $200 trade-in.
**For those having difficulty: the trade-in is done by the person/company that activates cell phones, using their computer/POS system, not Target's system, Target employees cannot do this. If the Target store you go to does not sell cell phones and/or activate them (deal with cell plans and such), then they probably won't do this. If they do sell cell phones, just go to that part of the store, if that person will not help you, then go to management. Here's the link to the trade in page, where, until the 9th, there is a red box on left that states the $200 deal, click on it for details, text the link to yourself or something, bring it with you:
http://www.targettradeinprogram.com