Prices differ from shelve to pay point

I needed fitted sheets for my bed. I selected 2 sheets from the shelve. I checked the price tag on the shelve and made sure both the sheets are the same price. At the pay point the price suddenly increased by large amount. I pointed out that the shelve price was lower. I was told that the price tag is a "FROM" price displayed going upwards. But there is no price tags on the items itself. Now I do not go to a shelve and work on a "FROM" price. I need a definitive price and not a "FROM" price. Sheet street it may not be worth anything to you, but you have lost me as a client.