We hada swindle in Ascension (oh how the thread twists - but no one wore berets, or any caps come to that).
We used to pay in to it and get coffee, milk etc. Then I noticed aircrew often wanted a can of fizz. NAAFI at Travellers stocked Coke. I then discovered that NAAFI in Georgetown sold a dozen varieties of fizz at lower prices. Game on.
I charged Traveller's prices but offered a wider range of drinks, most not available up the hill. We made a hansom profit, sufficient to sub Sqn Ldr Ops when he 'lunched-out' a departing member of Ops at the Club in George Town. Everyone happy.
I also had to audit the Wives Club at Waddo. I pointed out to OC PMS that the annual turnover in the Wives Club was marginally less than my day's pay and I had to audit them 4 times per year. We stopped the audit.
Had to audit the ATC account at Lossie, nightmare, they were plus or minus a number of kegs of beer every month.