When is it worth driving across the Twin Cities for cheap gas?

Gas stations in some Twin Cities suburbs are 80 cents cheaper than others, but the numbers show it usually doesn't make sense to drive out of the way for lower prices at the pump.

(FOX 9) - Gas stations in some Twin Cities suburbs are 80 cents cheaper than others, but the numbers show it usually doesn't make sense to drive out of the way for lower prices at the pump.

Gas prices are finally falling in the Metro, where the average for a gallon of regular unleaded was $4.49 on Wednesday, according to AAA. The prices are uneven in different areas because of a variety of factors -- including differences in purchasing contracts and potential price wars.

Driving across town

Let's say you live in Eden Prairie, where most stations were selling for the Metro-wide average of $4.49 per gallon, and noticed that stations in Hastings were selling for $3.68. Should you make the drive?

The 70-mile round trip would require 2.8 gallons of gas for an average car, costing $10.30 at the cheaper Hastings price. The fill-up would save $11.34, creating a net gain of $1.04.

But gas isn't the only cost of operating a car. There's insurance, oil changes, and wear and tear on the vehicle.

The federal mileage reimbursement rate of 62 cents per mile attempts to factor in these costs. Using this, the drive from Eden Prairie to Hastings and back would cost $43.40, way more than the $11.34 saved.

To break even, you'd need to live within nine miles of the gas station. That's roughly the distance from Hastings to Cottage Grove.

When to compare prices?

Price differences are typically much smaller, 10 cents or less per gallon, creating a savings of just $1 or $2 per fill-up.

Using a cellphone app like GasBuddy or Waze does make sense if you limit your search to stations that are very close to your home or work or are directly on your commute.

There are loyalty programs and other offers to consider, said Patrick De Haan at GasBuddy.

"Be aware of how you pay. Some stations offer free loyalty programs that you can sign up for that save 3-5 cents," he said. "There are also credit cards that offer rewards on purchases. So there are a lot of ways to save."

Club stores

Club stores like Sam's Club and Costco sell gas at leaner profit margins than their gas station competitors, generating a savings for their members. Doing so encourages people to sign up for memberships and shop regularly at the stores that share a parking lot with the gas stations.

The Costco in Eden Prairie had a gallon of regular unleaded for $4.16 on Wednesday, 33 cents cheaper than the nearest Holiday.

That would save the average driver $4.62 per gallon, meaning the driver would need to fill up 13 times to break even on the $60 annual membership at regular price. (The regular price for an annual membership at Sam's Club is $45.)

One disadvantage: there's often a line of cars waiting to fill up.