https://www.gamespot.com/articles/last-chance-free-and-cheap-pc-games-in-gogs-big-su/1100-6459372/

Anyone who wants to save money on PC games is in luck because GOG has kicked off a massive summer sale, with over 1,000 games available for up to 90 percent off. They're even throwing some free PC games into the mix, some of which are only available for a limited time. The sale runs between now and June 18 and, as always with GOG, the games are DRM-free. [Update: It's now June 18, giving you just a few more hours to take advantage of this sale.]

Two games are easy to get for free. If you spend $5 on games during the summer sale, you'll get a free copy of Sunless Sea, a roguelike survival game set in a watery, apocalyptic version of London. Spend $20, and you'll unlock Rime, a game of puzzle-solving and exploration that takes place on a mysterious island.