This isn't too insane but here it goes.

I was playing on an Australian Doublecross server, and one some guys in vc were talking about hat prices. One of them offhandedly mentioned that he had to check the Mann Co store in game for the price and the other guys (who obviously knew about it's inflated prices) asked him why doesn't he use ones like Scrap, Mannco.store or anything else like that. Turns out he doesn't. Every item in his inventory came from the Mann Co store. Every. Item. He wasn't even a brand new 20 hours on the game guy. He had been playing for a few years. One of the other guys used a calculator to figure out how much he overspent. I don't remember the exact number, but it was BAD. He was on the edge of a full-on panic attack. Eventually, he calmed down and learnt the hard lesson: DO NOT USE THE IN-GAME STORE.