…or rather, “someone else pays for it.”
My Team Fortress 2 buddies have seriously gotten into Mann vs. Machine mode, and I was recruited as a reliable Engineer. I spent somewhere in the neighborhood of $10 on tickets and a backpack expander. I certainly don’t begrudge Valve the money, given how much play time I have gotten from TF2.
The last time we completed a tour, I received a professional sniper rifle killstreak kit. For non-TF2 people, that is a fancy cosmetic item that attaches to the standard weapon for a popular class, but it takes a bunch of other resources to use it. And, to my shock, it sells for about $50 on the Steam market. Mine sold for that in about a week, which netted enough in my Steam wallet to pay for my initial cost, then all the MvM tickets I am likely to use this year, and then a game or two besides.
I am happy to take the sponsorship, although I am shaky on why one might spend that much on one component for one cosmetic item for one weapon for one class in a game. Maybe it is a really nice cosmetic item. As it is, there are apparently people who are willing to sponsor me to play games with my friends and get bonus items, as long as they get one of the rarer bonus items. Pro circuit it’s not, but deal.