the buy here pay here lots are the worst at jacking up prices, what they do is put a high price tag on it, and they tell you for 3k down we can meet any terms you want, what they dont tell you is that the down payment they sell it to you for is what they paid for it in auction, so by the time you leave they have made their money back, and then any payment you make is straight profit...
also they are counting on you to not be able to make your payments and let it get repossessed, which then they turn around and sell it again, for the same money down and what ever payments the next buyer agrees to, and then they just doubled their money in selling it and not even counting the payments all parties makes...
like you said best way to do it is sell it on your own...
i learned alot selling cars for the few years i sold em, although i made some good connections and learned a LOAD of info