If you want a guess at value that is one thing, If you want an 'appraisal' for insurance value, that is all together different.
Most places that are recognized will charge you 35-50 bucks for an appraisal that will hold up in a legal battle. You will also have to pay them to testify if it comes to that.
I know a guy in Olympia, that has won court cases. Let me know if you want his name.
Carl