You used to be able to charge the customer every time the card was used which was 50p. This was stopped some time ago and the business had to pay it so most brought in a minimum spend or else they would make a loss on the sale. Now a lot of card companies only charge the business owner a percentage fee so you can afford to let customers use their card for smaller amounts.
Smart Meters. Am I being over-charged?
To think that London, or anywhere else for that matter, does not belong to any one demographic