Hi, Ebay and amazon.com are good places to sell a tablet. If you want to try to sell it here, post a good clear photo of it with the model number and description and list of parts that you have and the price. Mention whether or not shipping cost is included in the price. And you could start a thread in the hardware section of this forum... or digital art section.
I'm not so certain that I could buy anything, but it may help you sell it if you tell people what kind of tablet it is and what shape it's in. How many nibs are left and all that, too?