Fair warning: lots of roguelikes on this list. Just seems like the devs of these games really like 2d non-demanding visuals. And I don’t know how low do you need to go, so check these individually.

Don’t even need a sale for Moonring, which is a retro turn-based RPG, completely free. Runs on a potato.

Original Monster Train should work decently well, it’s 90% off.

Shogun Showdown is really cool, 50% off. Necesse is a very fun Terraria-like, coming out of EA in like a week and on sale now.

Look into Reus 2, very fun, but it’s got some more visual effects so may be a bit too much. Same with Astral Ascent, one of my fave action roguelikes but, well, it’s action. Needs a decent framerate. Same with Dead Cells, Cult of the Lamb and Chronicon - great games, 2d, but may require a basic dedicated video card or a beefy integrated one.

Spellcaster University is not a forever game but it’ll be fun for a while.

Cook Serve Delicious series is really good. You can start with 1, they are each a bit different.

Cross Code if you want an RPG. Citizen Sleeper or Road Warden if you want an RPG that’s borderline a visual novel. Slay the Princess if you straight up want a visual novel.

Library of Ruina and Lobotomy Corporation if you’re a masochist who likes a good story.

Then there’s eternal classics like Stardew Valley, Balatro, Terraria,FTL, Into the Breach, Slay the Spire or Binding of Isaac: Rebirth.

And on the incredibly niche side of things, I recommend Intergalactic Fishing and Rings of Saturn.

Hopefully something from this list catches your fancy!