I personally wouldn't sell it. I'd junk it or maybe donate it to Goodwill. Disclaimers are pretty useless because many people don't read them so you end up causing yourself and the buyer grief. And you have to ask yourself would you be happy with a device that you need to charge on a daily basis that's supposed to last longer than that?
If you're not happy with it why would someone else be? And why would that someone else pay you good money for it + shipping. What would you sell it for? $5? $10? Plus shipping they're nearing $20 and someone could take that $20 and put it towards a newer reader. You'd only be disappointing someone by selling something to them that's on it's last legs. That's not a good experience.
It's up to you obviously but since you asked, I wouldn't sell it. I'd donate it to Goodwill. They can make some money and maybe someone who can't afford to buy a new reader can use one on the cheap for even a little while.