I just bought a house. This is important because it means I have no money. Having no money means that in order to get my gaming fix, I have to play stuff I've already got in my collection (which, to be fair, is substantial) or find games I can play for free.
If you, like me, have free gaming hours but very little money to spend, I have news for you: there are loads of free games you can legally download and play. I've pulled together a few that I've had a go at. While some of these games allow microtransactions, none of them impede play by making you pay to win or buy "energy" to keep going.
Pandemic 2
Pandemic 2 (not related to the co-op board game Pandemic) is a flash-based strategy game you can play for free in your browser. In it, you play as a deadly virus trying to infect the entire planet. As you play, countries will make it tough for you by shutting down airports and shipyards, and you'll have to find a way to overcome them.