Hi, Z. . .welcome to the boards.
As far as a "free" nano or IPhone, and speaking ONLY from experience (as I have not seen any of these offers), my best guess would be: CAVEAT EMPTOR!! I think it's HIGHLY unlikely that you're going to find a free offer for either a nano or IPhone unless there's a BIG HOOK at the other end of such an offer. If any of them have a phone number listed (highly doubtful), you might call them and see what the terms are as it seems they must not be listed on the offer itself. Unless it is a telephone service provider that will give you a free phone if you sign a contract for a number of years (which is pretty common - but I don't think I've ever seen such an offer for an iPhone or nano), then I think what you've run into are simply come on's, hoping you'll bite on the bait and be stuck getting a gazillion bits of spam or some other non-desirable result from accepting it.