I'm guessing Walmart or Costco. No fitting rooms though. 12,000 RPM doesn't strike me as
a coupon cutter but maybe he is. More likely, my guess, is that he just doesn't shop for shirts and pants and relies on his wife, parents, and in-laws to buy him those things for his birthday and Christmas.
Also an adult male can get away with wearing the same 10 -
20 shirts and same 10 pants year after year if you don't need fancy clothes for work. I haven't bought a suit for 15 years. I've gotten 4 of them from close relatives in that time.