If you have a friend or family member who already owns GMod on Steam, you can ask them to add you as a friend and share their game with you. This method requires an existing Steam account, but it's a great way to access GMod without spending money.
However, there are several drawbacks to consider: free steam account with gmod
Garry’s Mod (GMod) for free is a popular request, but searching for "free Steam accounts" can be incredibly risky. Most sites promising these accounts are scams designed to steal your personal data or infect your computer with malware If you have a friend or family member