Just a little story about buying tiles.
We were buying some tiles in Leclerc. The notice above the tiles said 12.90€/m2 and just below in much smaller writing was 19.35€ per box. This was a pile of boxes and a lot of the boxes had broken tiles in them. At the till I queried the bill and it was correct so no problem. A short while later we decided to use them for a different shower and decided to return for some more. This time it was more difficult to find enough boxes of unbroken tiles so had to move several boxes of broken ones. On removing one of the boxes my husband held up a large sheet of paper which showed that the price of 19.35€ had been crossed out and replaced with 19.35€ per box and by two boxes get one free! So we take three more boxes to the checkout with this sheet of paper and query it. After about 6 different phone calls by the information desk we not only came away with three boxes of extra tiles but also a €16 refund as well for the original amount we paid. So the moral of the story is check your receipts, keep them and do not be afraid to query the bill!
Another place we wanted only half a boxful of tiles and despite there being several loose tiles they were not prepared to sell us them and we were not prepared to buy a whole box so they got no sale at all!