Thrifty - thrifty rate @ carrental.com

I don't have much experience in car rental. Yesterday, I checked rate at carrental.com and reserved at a low rate ($287.94 for a week, standard. pick up @ SAN airport and drop off @ LAS airport) with thrifty. This rate is much lower than the $480 quote I received from the same website before and even now.
Could anyone explain what could be reason for this? Is it simply the luck, price error, or common deals? Thanks.

Does that rate include Thrifty's separately itemized, per-rental, drop charge?

On Thrifty's website, it shows the base rate you were quoted, a $330 drop charge, and a total of $736/wk.

Dollar/Thrifty have a different business model when it comes to one-ways. Rather than a higher daily rate like Hertz, Avis, and National, they have the same base rate plus a flat drop charge, no matter how many days you keep the car. So the "premium" brands are better for long distance, short time, and the "discount" brands can be better for short distance, long time.

informative reply. thanks. i will check with thrifty