Dear Cashing In,

I'm planning a family vacation this summer to the national parks out West. I have airfare and lodging lined up, and the only other major expense is a rental car. Are there any cards that can help with rental cars? 

- Natasha

Dear Natasha,

That sounds like a wonderful trip -- the great outdoors, national parks and plenty of family togetherness. A rewards credit card may be able to help you get there in a rental car for less cash, but you need to know a few things first. 

Unlike airlines and hotels, rental car companies do not offer co-branded credit cards. If you were looking for free flights or hotel nights, co-branded cards often have sign-up bonuses that can really help. But with rental cars, you're out of luck on those kinds of cards.

It looks to me as though a minivan rental for a week from, say, Salt Lake City, would run you somewhere around $600, including taxes and fees. 

With the right sign-up bonus on the right card, you might be able to knock down a big chunk of that.

You might look at cards offered by banks that offer generic travel rewards. For instance, take the Barclaycard Arrival World MasterCard ($89 annual fee, waived first year). If you spend $1,000 in the first 90 days, you'll earn 40,000 miles on that card, which you can redeem for $400 worth of travel expenditures, such as those with airlines, tour operators, hotels, cruise lines -- and rental car companies. The way it works is you pay for it as an expense, then request reimbursement in the form of a statement credit, which, according to the card's terms and conditions, is supposed to post in five to seven business days.

That appears to be one of the more generous bonuses on cards in that category. Cards that work in a similar way include the Capital One Venture Rewards card ($59 annual fee, waived first year), which offers 20,000 miles (a $200 value) if you spend $2,000 in the first three months; and the BankAmericard Travel Rewards card (no annual fee), which offers 10,000 points (a $100 value) if you spend $500 in the first 90 days.

If you have any available miles or points in credit card programs, you might check the online malls associated with those cards. For instance, you can redeem American Express Membership Rewards for gift cards at Avis, Hertz and Enterprise (at a rate of $50 off per 5,000 points). 

If none of these options suits your fancy, just keep on the lookout for rental car coupons. Once you start keeping an eye out for them, you'll see them all over the place: at warehouse clubs, inside some credit card bills, in coupon books. You can even just search the web for "rental car coupons" and come up with some small price breaks that beat simply going to the car companies' sites right off the bat.

Also, while we're on the topic, be mindful of the insurance coverage you have when you use a credit card to rent a car

Happy travels!

See related: How do generic miles stack up against airline rewards?, Renting a car? Beware of phantom toll fee charges, Frequent car rentals with debit card shouldn't clobber credit