What is one worth?

It all depends on the condition and the owner. Since its more than 25 years old, some people will consider it a classic. Others will call it an old piece of junk and practically give it to you. Finding one may be a difficult task as well depending on your location. They're very popular in north-west United States and all of Western Canada. I'd expect one in great working order to go from anywhere in the $4000-$7000 range just because its so old and finding something like that would be a gem.