My neighbor growing up owned brokerage for refurbished aircraft parts (apparently there is a niche for everything). They'd refurbish some stuff in house but farmed a lot of it out. Anyway, one day he was giving me a tour of his office and they had a garage for storage in the back. He picked up this valve off the shelf, it was the size of an 80 count aspirin bottle. He said he bought it for $1200, spent another $900 to refurbish it and he was going to sell it for $5000. Absolutely mind boggling.