I have like $200 on steam. Every game I play i profit, that has trading. That's leftover from selling out of CS:GO, but I only buy steam items on winter/summer sales, and still only play 15-20% of the ones I buy. Have like 200 games, 40 installed, 0 i play regularly. I change in and out, but indie games are hella fun.
I would buy Black Mesa since I really love the Half life series. They aren't not done with the game yet though, so I don't know how much it would meet my expectations for it