Is there a way to port forward my localhost to make my developers be able to access the server without me having to spend money on a vps?
any port forwarding tutorial, for any game server, will work.
You just need to open port 30120 (fivem’s default), or whatever port you are using for the server.
Even on my own pc and ip?
Obviously, however do note that some ISPs (Internet Service Providers) may block port forwarding or direct connections; if you think you do it all right and it still refuses to work, contact your ISP support for assistance to make sure it’s not their fault.