Prices matter

I visited the Builders Warehouse at N1 city on 8 August 2023. I eventually only want to buy some thing small but end up buying something much bigger. On the shelf the price was R399.00 (fading away btw). When I need to pay the price was R529.00. I was told that you need to have a builder's card to get discount and then I need to take a catalog to see if it is in the catalog. Then back to the card. All of a sudden the price on the shelf was R539.00. I showed them the price on the shelf right were the item was. They argued with me the entire time. The manager mumbled something about R250, but quit frankly I dont care. I am tired of shops with different price at the till then on the shelves.