'That's expensive! Bloody hell! I could get XXXX for that. In 1972 you could get that for £2.51... rarrr rarrrr waffle wafflee moan moan moan'.
I don't work on a market stall. I don't make up the prices.
I don't stand at the supermarket checkout/ petrol station whatever and bitch on to the till operator about how much things cost.
If I need to ask the price and something costs more than I want to pay I'd say 'thank you' and leave.
AIBU to think these people have no social skills?