Walmart sells a head mount mini-light, $1. Low power, but useful.
Powered by two 2032 batteries. Those are sold in a two pack, $4
Trader Joe's stocks kelp in single bags, 0.4 oz, $1 The same product is offered in bulk, 6 bags in a package, each bag .17 oz, $3.50 per package.
Looks like my education is dated, I need remedial courses in economics and arithmetic - OK gang, you got any stories of products you were involved with, where the market price was preposterous?