Here is a somewhat hastily drawn outline of Leif's foot. Get them to stand on paper, putting full weight on it while you outline it. Don't get permanent marker on the white sock or you will hear about it and so will any people you run into for the rest of the day.
Eye ball it and say to yourself, "Man, I wish I would have cut this out at home."
Track down a scissor from a work station at Wal-mart and then match your foot to a shoe.
Shoe shopping rescue tip! TA-DA!