>MANY years ago I was with a friend in caravan holidaying camp, in the cafe. There was advertised a coke floate, at 2s 4d (2 shillings and four-pence - equiv. to c. 12p). I asked the girl at the counter how much each was individually (the ice cream and a bottle of Coke) and that came to 1s 9d (= 8.5p), so I bought the makings individually and made my own.
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>A bit later this guy comes in, sees what I'm supping and orders one for himself. The girl gives him the makings and charges him 2s 4d. Go figure!

On a similar location, there was a bread kiosk. The loaves were 1kg in size, but since we have a cult of fresh bread (meaning that nobody likes yesterday's bread), they'd buy halves. The girl would cut it, put it very briefly on the scale (which she located behind the shade so you couldn't really see it) and would say "this half is heavier by 0.20 dinars"... until one guy said "OK, then, give me the other half which is that much cheaper."