Where is the value?

Long time ago, when travel was still possible and people still went on holiday, every morning I went to get provisions for the day at the local grocer in the seaside town where we were staying. And every time I could not help noticing his peculiar way of selling soft drinks. For the shopkeeper was selling the exact same drinks for two different prices, one roughly 10p higher than the other. I say “exact” but there was actually one difference: the cheaper one simply stood on a shelf, while the more expensive one was in the chiller. ….[READ]