Yeah, it's common to most stores with cash register generated receipts which are printed on thermal paper - it's both faster and cheaper for the stores. You can store them in a cool, dark, dry place to slow the fade, but if it's something you need to keep the only proven way to save the information is to scan the receipt as soon as you can. Temperature swings, especially in a car will affect them quickly, and any type of oils (like from food or plastics) erases them very fast.