Once you buy a game on Steam, you don't need to pay any kind of subscription to play it. The vast majority of games sold there are, in fact, one-time purchases.

Once you buy a game on Steam, you don't need to pay any kind of subscription to play it. The vast majority of games sold there are, in fact, one-time purchases. The games stay in your library even if the developer/publisher decides to delist them. There are games like MMOs that do require a subscription, but that has nothing to do with Steam itself.