Check out your local classified ads, and eBay. I sold a 20 year old piano for $600 that cost me $2000 originally and needed work. If its in any kind of good condition it should hold its value pretty well. If the exterior is in good shape, all the keys work, and it holds its tune, you should do OK. Most people looking for "starter" pianos are in the $500 - $1000 range. I don't know anything about the make you have, but if its a better quality piano, you should be able to get more.