Does that mean you won/accumulated 15k miles for flying those trips? Or that you "used up" 15k miles to get the flights just for $200.

Yeah, I'm not willing to spend much money for status/business upgrades, but if it's possible without spending major $ it'd be nice.

Can you give me a rough idea of how many miles are required to get an upgrade, and how many you'd get e.g. on a US->Europe trip? I know it varies a lot between airlines and such, but I'm just trying to get an idea of the orders of magnitude involved here!