That's a very small pool table! Most pool tables are around 8 ft long.
From reading your message, I dont know if you have the whole table or just the slate. If you have the whole table, call some pool supply strores and ask the what a USED table would cost (your size).
If you only have the slate, it'll probably be hard to find a local buyer, since you dont want to pay the price to ship it, and is not likely an item in demand. Maybe it can be used under a wood stove.... Try Craigslist!