Halloween // Trench coat needed

Planning on putting my spin on the classic 2 kids in a trench coat gag with me and my friend. The problem is that we aren’t exactly in the size range of people that can easily pull this off. Im 5’11 and he is 5’3 (him on top, me on bottom) so i don’t know if any regular trench coat would cover the two of us and make the illusion work. Any suggestions for a trench coat that would do the trick? Preferably below $100?