Hi-- I have a harp that I’m considering selling, but have no good way to place a value on it.
It’s a 25 string lap harp that I built from a kit (Heartland Harps). These folks still make beautiful harps, but not kits. I built this back in the early 90’s, I’m guessing. It has C and F sharping levers and is in good shape.
Any ideas for a fair asking price? No “It’s worth $25.00, where do I send the check?” please 
Dave (harpmaker) is at a festival this weekend, but he may be able to give you some general idea of value when he gets back.
The going rate for a new 25 string harp with the partial levers you describe starts at about $600 and goes up from there depending on the maker.
However, since this was a kit, that decreases the potential value quite a bit. It is also hard to try to place a value because any kit built instrument will vary wildly in final quality.
You’ve got one thing going in your favor is that if I remember right, the Heartland kit was one of the better ones.
If you did a good job on the kit; tight joints, no glue marks, excellant finish without runs or drips, you should be able to get around $400 for it.