Here’s a little tutorial on creating buy zones,
Create a brush around your player spawn/spawns with the trigger texture; this brush defines the size of your buy zone. It should touch the floor and be as tall as your player spawn entity, I like to have mine 16 units higher then my player spawn entities.
Now that you have the area defined for your buy zone you actually need to turn it into one. So select your brush and right click, scroll down to “tie to entity” and left click alternatively you can select your brush and just hit Ctrl+T. This will make the object properties window pop up. Now expand the “Class” pop down menu and scroll down to func_buyzone then left click.
All that’s left to do now is make it either a Counter Terrorist spawn or a Terrorist spawn. You can do this be clicking on the “Team Number (int)” option in “Keyvalues” then using the op down menu either choose “terrorist” or “Counter Terrorist.” Hit apply and you’re all done go compile and try out your shiny new buy zones.
If you have more than one buy zone for one team it’s a good idea to name them, just click on “Name” in “Keyvalues” and type what ever you want to call your buy zones, remember names cannot have spaces in.
Hope this has helped.