Originally Posted by LoganFlyer
One thing that I've heard is cheaper is to start by doing a one way SEA-SFO, but return the car immediately upon arrival. Then rent another car for the week at SFO. I haven't tried it myself.
yes, this is the BEST way to do it. The best one way rates always are "per mile" rates. Rarely are they unlimited mileage. Return the car immediately, then use your best rate code to get the best rate for the remainder of your trip.