I think we all said $1000 is the minimum you should get back. Given you are going to have to sink at least that into it to get a car in drivable condition, I'd say you should get more. Not disclosing that scratch is also deplorable.. what is it with people that makes them think the internet gives them license to be a lying thief?
And you don't need a lawyer to go to small claims court. Just have to do a little reserach and pay the filing fee. Check with your county government for the specifics. Because he is in the military you have another card to play, namely writing a letter to his commanding officer, explaining to him just how dishonest he is, they won't take that lightly and he really won't want you to do it.