Just play CS GO or Team Fortress 2 and sell the loot outside Steam for cash or Bitcoins. By the way Steam allows buying of games with Bitcoins. And I like to play an offline game called a job where I can earn the cash so as to enjoy online games that I play just for fun 
Haha I kinda know what you feel playing your favorite game while earning money.
Its like hitting two birds in one stone
I thought to offer your service like levelling job, you can play and earning some money at the same time and this is possible for doing your favourite game at the same time.