Disgusted in the alcohol prices

Wow the experience with the open air cinema and even the helpfulness and friendliness of staff at last nights event held in kirstenbosch amazing, the vendors food amazing and reasonably priced but the only dissapointmemt i had was their liqour vendor. Please explain how you charge 40 bucks for a beer and think thats a reasonable mark up. Thats triple what a 500mil can costs and its rediculous. If those cans cost approximately 15 bucks how and who allows this type of thievery to take place. Common guys we paying for an amazing experience and the other vendors were reasonably priced so where do you get the gaul to charge people triple the amount because 2 cans equates to a 6 packs money. This needs to be revised because a 10 rand mark up is more than suitable in my opinion so im actually disgusted and dissapointed in this regard. Three tins costed us R145 bucks nah gents this is daylight robery and you know it for a fact. Had it been a extra ten bucks added making it 25 bucks a can you would have still turned a profit. I am disgusted.