If you are handy with CodeWalker (the GTA V map editor), you can take the vanilla GTA V police station (the one from single-player) and add your own props, lockers, and doors. There are dozens of YouTube tutorials on "How to map a PD for free using CodeWalker."
For servers with a focus on county roleplay, the Paleto Bay station is essential. Free versions often transform the small office into a full courthouse and jail complex.
This popular community release has been specifically patched with YBN edits (collision fixes), extra lighting, and updated occlusion to ensure it runs smoothly on modern FiveM builds.
In the FiveM modding community, "patched" usually refers to fixing common bugs like flickering textures, falling through floors, or door collisions that stop working after a GTA V base game update. Common Fixes for Free Police Station MLOs
If you typed into Google, you are likely frustrated. You want to build a cool RP server for your friends, but you don't have $120 to spend on a high-end PD.