They’ve declared my vehicle a total loss but won’t pay me enough to replace it. Is that legal?

The company owes you the actual cash value of a comparable vehicle in your local area. You can determine this amount by using dealer quotes and/or newspaper ads or other auto sales publications, as long as the vehicle being sold is comparable to yours in mileage, condition, options, etc. In addition they will pay you sales tax on the value of your vehicle, and pay the unused portion of your registration fees. You may have the option of keeping your car (called - retaining the salvage). If you do, the company will subtract the value of the salvage from the final settlement, as you are keeping the damaged car. (WAC 284-30-3901 through 284-30-3916)

From: Washington Insurance Commissioner Fact Sheet