Two marked prices

The_Pedant

The OP offered to buy it at a price and the shop accepted

The point I was making is that often people make a number of purchases & it is not until you get home sometimes that you realise the price you saw did not match the price you were charged (well do you meticulously inspect every item on your receipt at Tescos before you leave the till?) No, quite possibly not.

The argument for people switching prices is a moot one.
If you are caught doing this and try to get through the till then you're clearly committing an offence. Additionally you have to rely on the staff not actually spotting it's a different item. If it's a question of completely the wrong label then again the store are covered.

However, where they have clearly hiked a price up & left the old price on then I would say that it is still reasonable to expect the lower price, even if you did not spot you had actually been charged the higher price.