I have one of those wine bottle foil-cutters. It was a freebie with something or other, not sure what. Completely useless; I always use the tip of the corkscrew to prise/peel off the top of the foil before taking the cork out.
I had no idea such a thing existed. I have a corkscrew with a small knife in it, but I didn't know they sold foil-cutters as a separate tool.
It's a really stupid device that doesn't work properly. I would never pay for something like it; it was a corporate freebie of some sort. I actually want to say a drug rep gave it to me after a presentation they did on an anti-alcoholism drug, but that's probably just my memory confabulating a better origin story for it...
It's sort of like this one I just googled up: http://www.chinadong.com/upload/2009...oil-Cutter.jpg