If you’ve ever wondered, there are indeed better times of the week to fill your car up with gasoline. According to GasBuddy.com, you’re most likely to find the cheapest gas on the weekend.
 GasBuddy.com studies gas prices over a four year period and found that Friday,Saturday and Sunday had the lowest prices for 65% of states in their study of gas trends. 
Additionally, very few states saw the mid-week, Tuesday or Wednesday, as the best days for lower gas prices.