Buy a snickers bar or chocolate bar, then before you leave use the restroom, go in a stall, and rub it in your hands so it melts. Put the chocobar in the toilet seat or on the floor, and wipe a little on some toilet paper, and stick it to under your shoe.
Flush and leave the stall, keeping the rest of the chocobar on the floor/seat, and go back through Walmart buying stuff in style