wait for a Steam sale.

Not sure why someone in this community would suggest Steam over GOG. Every game on GOG is DRM-free, so you own it forever and the installer will keep working even if GOG goes away.

Games on Steam are a license they can revoke at any time. You don't actually own the game. Some games are DRM-free, but there's no way to get a standalone installer for them.

Some people pirate or crack games they legally own, just so they have more flexibility and aren't treated like a criminal by DRM systems. You don't need to worry about that with GOG.