Want to save money? Gas up your car on Monday, never Friday

With the warmer weather comes those higher gas prices.

Experts say prices at the pump are the highest we've seen in four years, but GasBuddy says you can save by shopping for gas on a specific day.

Turns out that Mondays are the best day to go. This day offers the lowest average gas prices across 21 states.

This means Fridays are also the worst time to fill up.

If you want to get ahead of the weekend traffic and if you're just looking to avoid the long lines, Sundays are your best bet, GasBuddy says.