I would say $100. The last car I did that in was a 20-year old Mercury Sable. One thing I noticed was in Arizona the roads are nice and smooth since there is not much traffic. In California I-5 is fast but pretty worn. This was 10 years ago. The rest stops in AZ had vending machines but in California there was nothng.
It s about 800 miles, each way, with it being freeway most of the distance. Figure out what kind of freeway mileage you get on your car and do the simple math.
It is 765 miles, you can finish it in one or two days, gas costs $90 to $100 one-way
3 -4 tank of gas.