I've never paid close to $1000 a week. What companies have you checked?

if you are trying to rent in one isolated location and drop it off in another, or are under 25, maybe I could see 2000-3000 but other wise I can;t imagine where you are looking.

I randomly checked San Diego-San Diego and San Diego-San Francisco for the period August 3-August 24th, and came up with about $600 for a Ford Focus.

First of all, don't rent at the airport, there are a bunch of extra "fees" tacked on.

Second, try to bring the car back to the origin to save drop-off charges.

Third, determine the car you are interested in, and check with new car automobile dealers, as they will 'lease' a car for several weeks.

You can look for discounts from the rental companies. If you are a member of the AAA, or belong to an organization that offers discounts such as alumni associations or professional associations or discount shopping clubs.
Weekly rental rates are always better than shorter term rates. check the price of a monthly rental and see if it is cheaper per day even if you dont need it for a month.
Do you have insurance that will cover you for personal injury in the event of an accident?
An option for collision damage coverage.. if you have an American Express card, you can enroll free in their insurance program for rental cars, and it will cost you a total of $25 for the entire 3 weeks and you get decent coverage for the car.. its not coverage for your person. Its much cheaper than the coverage given by the rental companies. and for 3 weeks its best to have coverage as you dont want to pay for any dings you may get in a parking lot.

car dealerships are not likely to rent to you for a month unless you are insuring the car.

the major rental companies do not require that you pay in advance.. you can reserve a car and the closer to your rental date you can check and see if the price drops and then reserve again and cancel the more expensive reservation.

California is a rather large state. Where are you entering CA?
Which town/cities do you want to visit?
Do you own a car which is insured in the US?
It might be cheaper to fly to Las Vegas NV and rent a car there for 3 weeks returning the car there and flying home from there.

Have you tried comparing the car rental prices on vroomvroomvroom or expedia etc... ?

We are going to California for Christmas and rented one using speedyrentalcars.com, this is about the 4th time we're using them and if it ain't broke, don't fix it.

michaelq - looks like Speedy is a third party renting cars for folks.

I'm not that lazy to not search around myself first.

Although not in California, I have gotten my best rental car deals through Priceline.

Have you checked aaa.com?

Or, if you are flying, you could check to see if there is a good rate offered in conjunction with your airline. I got a good rate, and a lot of bonus points, by using a Southwest-affiliated car rental sale last summer.