i'm sure he's not putting expensive loads through a gun that he's shooting at a bunch of soda bottles, plus i'm pretty sure he was focused on having the least kick possible so why wouldn't he be shooting trap loads.
and i went back and watched more carefully, definitely less than 10 boxes, even if he was paying for premium loads he spent less than 100 bucks, not nearly the 500 as whoever said.
sticking to my estimate of 40 dollars of shells.