This really depends. Do you have the tech package on your FX? Or do you have just the plain non-intelligent key remote, that anyone can just program? You can get any of the actual keyfobs on ebay cheap, do it. Make sure the FCC IDs match up, like Ed said. But some keys are different too. When I got my 45 with the intelligent key last week, one of the keys was missing in the fob. So I ordered a blank one cheap on eBay, but its missing that chip inside to start the car, so that's probably why it costs so much to program at the dealer. I don't know where to get that chip at the moment either.