Got some free time over the next three weeks? Delta just launched a promo offering 9,999 miles for each rental with one of their auto partners Avis or Budget. Each qualifying rental gets you the miles, regardless of how long you keep the vehicle, as long as you book with Delta's Car Search tool. You have until the end of the month to rent and you need to sign up to become a SkyMiles member first.

Sure, you may not be traveling three times in the next month, but do you need to? If you can get three car rentals cheap enough, the time and money invested in getting a car at the airport for 24 hours can easily be less than a domestic ticket that you could book with miles.

Rental car fees vary wildly across geographical boundaries, but almost every airport in the country has either an Avis or a Budget rental car location. And many of those rural locations have plenty of inventory (at damn good prices) available for the rest of July.

Here in Detroit, a car rental over a weekend night on Budget is about 55$. Times three is 165$ for 29,997 miles or an award ticket. In Kalamazoo, a more rural airport near where my parents live, it's 24$. That's 72$ for a flight.

Sure, you have to factor in what you're going to DO with the car and what you're going to do with YOUR car while you have the rental. You could always just take it home or to a parking lot and park it. Or park it on the lawn of the rental company.

But it's not a bad way to rack up a few frequent flyer miles to use for future adventure on Delta Airlines.

What could you do with 25k miles or a domestic award ticket? You could fly from your freezing hometown in New Hampshire down to Phoenix next January to get some sun and play some golf while your coworkers freeze. You could fly to Colorado to get some kick ass skiing in next May. You could pay for your girlfriend to come visit you next time you're in San Diego on business.

Sound like a good use for your 74$ invested this month?

Filed under: Airlines, Budget Travel, Travel Deals