I was in WalMart today and took a look at the prices for various motor oils. Pretty interesting. Right now I am using Castrol High Mileage 5W30 in my car. For about $14.00 you can get a five quart container of this oil. Heck, for around 4 bucks more you can get five quarts of Penzoil Platinum synthetic oil. The Mobil 1 5W30 five quarts was something like $22.00. If you want to go conventional you can get five quarts of Valvoline 5W30 for less then 10 bucks. Anyway it is cheaper to go with the five quart container which you can then use to return the used oil to a recycling center. If you like conventional oil the Valvoline conventional in five quart containers makes oil changes about as cheap as you can go. Maybe the Valvoline is not the greatest oil but 3000 mile oil changes sure are tempting at that price. The Penzoil Platinum sure looks tempting. For about what I pay now for Castrol HM you could be using the Penzoil synthetic oil. The Mobil 1 is more costly, especially the Extended Mileage. It was close to $30.00 per five quarts.