They do work
I too, have received a iPod Mini, a Toshiba 24" TV/VCR/DVD combo (and they even paid the shipping for that beast!!!) and a $500 Bank of America gift card (VISA)
So, it does work... of course, there are offers to complete but sometimes, these are offers that you might be looking for and even if they cost marginally more than something you might have priced out yourself, the free product in the end tips the balance in your favor.
Echoing the previous poster, I know Gratis is genuine - never had a problem with them or their customer service. ^