last fall I sold our 2 yo car that I still owed 10k on. I got a quote from carmax, 10.5. The stealership offered me 10 minus a whole lot of fees, so about 9. I sold it for 11.5 or 11.25, something around there. private party. I sold it to an aquaintance who was looking for a car with my car's particular features, they mentioned it on fb. we worked out a deal, and it was great. I would have listed it on craigslist if it hadnt just worked out. I think the kbb was around 12 or 13 for mine in excellent condition, which it was not perfect, but pretty good.
just an anecdote.