Ok so I'm sure that there are some people on here that keep their Gas receipts and turn them in tax time,weather for biz, company vehicle... Ok so what you do it say you plan on only buying $10 in gas. 1.Go INSIDE,pay with a hundred dollar bill. 2.Go back outside and pump your $10 worth of Gas. 3. Go back inside with your receipt and ask for your $90 back since you didnt pump it all. Now you have a receipt showing a $100 Purchase for gas when you actually only paid for $10.