Credit cards that will help you save money on gas

Dollar bill sticking out of gas tank

The cost of gas, now around the $4 mark on average nationally, can dramatically reduce what's in your wallet.

So it makes sense to squeeze out a bit of savings by paying with a credit card instead of with cash or your debit card.

Many credit cards offer cash-back rewards that can shave a few cents off each gallon. Over time, those pennies translate into significant savings.

But picking the best gas credit card isn’t as simple as choosing the one with the highest rewards. Some things to consider:

* Is there a cap on gas rewards?

* Are there limits on where you can fill up?

* Is there a spending threshold you must meet before the full rewards rate kicks in?

* Is the cash-back rebate year-round for gas or only at certain times?

* Is the annual percentage rate an introductory offer that will increase after a certain period of time?

* How long will it take for the card issuer to give you your rebate?

Besides those factors, also consider how much you drive and where you fill up your tank.

If you use your car primarily to commute to work and fill it up at the corner gas station, you might consider getting a card specific to that company.

But if you’re a road warrior or fill up at the cheapest station regardless of brand, it’s better to go with a card that can be used most anywhere.

Best all-purpose credit cards for gas rewards

If the only card perk you want is gas rebates, Pentagon Federal Credit Union gives you the best rate on gas, hands down, on its credit cards.

The PenFed Platinum Rewards card offers a 5% rebate on gas purchases, 3% on supermarket purchases and 1% on everything else. A second card, the Visa Platinum Cash Rewards credit card, also gives you 5% cash back on gas, but just 0.25% on everything else.

There are no spending caps, minimums or annual fee required.

Both credit cards have an introductory APR of 9.99% through June 2014. The APR for balance transfers is 4.99% if you get the card between now and June 30, 2012. After that, it increases to a variable 9.99%.

These are tougher credit cards than usual to get.

First, you’ll need excellent credit to qualify. Second, you must be a member of the Pentagon Federal Credit Union.

But even if you’re not employed at an eligible organization, you can still be a member by joining the National Military Family Association for $20. Once you are a PenFed member, you’re in for life. (Enroll at www.penfed.org.)

The American Express Blue Cash Preferred Card is ideal if you spend a lot on gas, groceries and clothes.

You get 3% rewards on gas and department store purchases, a whopping 6% on groceries and 1% on everything else.

The $75 annual fee is quickly erased by these high rewards rates, and you get unlimited cash back with no spending limits.

You also get a $150 cash-back bonus if you charge $1,000 in eligible purchases in the first three months.

If you’re against annual fees, American Express also offers the Blue Cash Everyday Card, which has no annual fee but reduces the rewards to 2% at gas stations and department stores, 3% at supermarkets and still 1% everywhere else.

If you spend an average of $200 per month at the gas pump, your estimated annual cash-back rewards will be $219 with the Preferred card and $177 with the Everyday card.

The Discover Open Road Card gives you 2% on the first $250 you spend on gas every month and 1% everywhere else.

There's no annual fee, and you’ll receive a 0% introductory purchase and balance-transfer APR for the first 15 months, then it increases to a variable 10.99% to 19.99%.

Best store credit cards

We generally warn against store credit cards, but if you regularly fill up at the gas station down the street, a credit card tied to a specific brand might be a good bet.

Just watch out for those interest rates. And make your payments on time -- the penalty rate for those who don’t goes as high as 30% on some of the branded credit cards.

The ExxonMobil MasterCard gives you 15 cents per gallon back on purchases made at Exxon and Mobil stations. For $4-a-gallon gas, that amounts to 3.75% off.

You also get 1% off of $6,000 in non-gas charges, 2% off of charges totaling between $6,000 and $10,000, then back down to 1% on all charges over the $10,000 mark.

Rebates are automatically redeemed when you use your card, but they’re only credited in increments of $10 and expire after 24 monthly billing cycles.

The APR is a variable 19.99% to 23.99%, and there is no annual fee.

The Gulf Platinum MasterCard gives a cash-back bonus of 3% at Gulf stations and 1% everywhere else (except other gas stations).

It comes with no annual fee, and an introductory APR of 0% on all balance transfers for the first six billing cycles. After that, both balance transfers and new purchases come with a rate of 13.74% or 17.74%, depending on your credit score.

Gulf has 2,500 gas stations located mostly in the Northeast United States.

The Marathon Visa is good at Marathon stations, located in the Southeast and Midwest.

Earn 25 cents per gallon when you put $1,000 or more on the card per month, 15 cents when you spend between $500 and $999 and 5 cents for card purchase under $500. When you earn $25 in rebates, you’ll get a $25 cash card to use at a Marathon station.

Rebates are unlimited, but they expire if not used within 24 months.

The APR is a variable 16.99% to 24.99%, and there is no annual fee.

If you prefer to fill up at Costco, the TrueEarnings Card from Costco and American Express gives you 3% cash back on Costco gas, as well as 3% rewards on restaurants, 2% on travel and 1% on everything else, including Costco purchases.

However, the 3% reward is limited to $3,000 in purchases per year; it pays 1% thereafter.

This card includes 0% introductory APR on all purchases for the first six months. After that, you'll pay a variable 15.24% (prime plus 11.99%).

There is no annual fee, but you must be a Costco member to apply.

If you're still unsure about which credit card to pick, compare these deals with the best credit card offers in our extensive database.