My post, linked to above, involves using a Hertz coupon code (997076) which is valid for weekend rentals of two days or more. That probably won't apply to casual travelers who want to get a car at DAL and drop it at DFW a few hours later. (And besides, 997076 does not work for one-way rentals.)

I do suggest looking at the Hertz site and putting in your specific rental times. I just tried for this Sunday, picking up at DAL at noon and dropping at DFW at 4pm, and the grand total was projected to be $28, which is a fair deal in my book.