A supermarket checkout that can calculate the price of a number of items.
As a shopper So I know how much an item costs I would like to be able to see its price
As a shopper So that I can buy an item I would like to be able to scan items at the checkout
As a shopper So that I know how much to pay I would like to be able to see a total for all scanned items
As a shopper So that I know how much to pay I would like to see all prices correctly formatted (£xx.xx)