If you stop by BP in the next few months and get a least 8 gallons of gas, you can get a code to enter online. When you have 5 codes they will send you a $10 Gift Card. Sometimes BP is more expensive, however with my calculations this is still a great deal.
For instance today BP-2.99 and QT- 2.93. I have a 16 gallon tank so my difference is 0.96 times this by 5 and we are still making at least $5 off of this deal. Now if you want to be really frugal, you could split a fill up into two and save even more.