Mystique LS Lock Nuts (NO KEY)

Hello, I recently purchased a used Mercury Mystique LS. As I was driving down the road the other day I had a tire blow. So like any other car owner, I had gotten out of my vehicle and got the jack and tire iron. As soon as I got the car jacked up i had a closer look at the lug nuts and realised they were all lock nuts. So I looked around for the key and could not find it anywhere. The lock nuts look like an oversized allen wrench would fit it. I'm stuck right now and have tried the socket wrench 20mil technique with plenty of other ideas that friends and family have suggested. Tires Plus says they can remove them but will cost up to 400 dollars, in wich case I do not have. Any help would be greatly appretiated. Thank you, Will