This is a model D10 hammered dulcimer. It was built in 1993. The strings and tuning are the same as the current D10; see the D10 info at here. There is a stinging and tuning chart here. The soundboard and back are made of Honduras mahogany (current wood is sapele), the bridges and probably the rails are walnut, and the pinblocks are maple.
As for the value, we often see used instruments in good condition selling for 70% - 75% of the price of a new instrument of the same model. A new D10 without a case is $775. The case in the photo is a C10A case, currently selling for $95.