An option to hiring a car, is to "deliver" a car. There are heaps of 'driveaway' schemes where someone wants to have their car delivered from one town to another.
My husband did a scheme like this from New York to Los Angeles once. He was given 7 days to drive someone's car (they relocated and flew) and had to pay a fee upfront, which was returned at the other end when he delivered the car. You pay for petrol; but essentially the use of the car was "free". It is limiting in that you have a set number of days to deliver the car - but you can choose the route you take.
I don't know if the scheme would be available between SF and LA. But it's worth looking it up to see if there is anything going. You won't be guaranteed of a SUV....
The dropoff fee you quoted seem exhorbitant. It used to be that there was no drop-off fee if you were within the "region" of Ca, Nevada, Arizona. We're doing a pick up in Miami and drop off in Orlando through Alamo. There is no drop-off fee; but it is a different state.