Sure, Airfarewatchdog has you covered for flights, but what to do about car rentals once you've reached your destination. Rates seem to be rising by the minute. Thankfully our friends at AutoSlash.com have shared a few handy tips to help keep your rental costs down this summer.

Rental rates can be less expensive at off-airport locations due to generally lower taxes, but this is not always the case. We recommend comparing both on and off airport locations if you want to get the best deal. Sometimes a cab ride to an off-airport location makes sense, other times the airport may actually be cheaper due to competition or an abundance of inventory.

Apply coupons and discount codes to lower your rate. Look on the rental company websites as well sites like AAA, AARP, Costco, USAA and others that you qualify for to find available discounts. Companies like Hertz even let you combine coupons and discount codes together, which can significantly lower your rate. AutoSlash applies coupons and discounts to your rental automatically.

Research insurance options before you leave. Standing at the rental counter on the receiving end of the 'hard sell' on insurance is not the time to think about your coverage. Find out ahead of time what your personal auto insurance and/or credit card cover you for. All coverage is not created equal, and even different credit cards from the same company offer varying levels of coverage. Taking the insurance offered by the rental company will provide peace of mind, but it will come at a price.

Fill up the tank yourself for savings. Prepaying for a tank of gas, or letting the rental company re-fill the tank upon return may be convenient, but you'll pay for the privilege. Filling up on the way back to the rental office is almost always less expensive than any of the other alternatives offered.

Rental rates change often. We recommend booking early and checking your rate periodically, especially as your pickup date approaches. If you find a lower rate, you can always re-book, since unlike airline tickets, most sites don't require a credit card for booking, so you're not locked in. AutoSlash takes this one step further by checking rates multiple times a day, and if rates drop, they re-book you to lock in the savings.

Keep these money saving tips in mind and -if you haven't already- check out AutoSlash to avoid those sky high rental rates.