Got it. We have something similar hear in the states. There is AAFES (Army and Air Force Exchange Service) where service members shop for goods, groceries and general services (barber shop, auto repair shop, etc). Some of the money generated there is put into the MWR program (Morale, Welfare and Recreation). The MWR runs leisure services, such as fitness centers, pools, marinas, bowling centers, golf courses, restaurants, etc which are usually free for service members and their dependents.
Yes, I recall the PX from my many visits when working and visiting US Navy sites.