You're a car salesman. Unless you do it on a volunteer basis, with no overhead whatsoever, in my eyes, you will always be screwing the buyer. (overcharging, if you like that term better)
It's nothing personal against YOU. That's your job, and I wish you well. But for someone that has bad credit, and has yet to say how much he has to put down, or what specifically he wants, I was offering the alternative, which I feel very strongly in favor of.
Maybe he just wants to have a newish reliable car and the assurance that someone competent has checked over the car for problems. Then perhaps you would be the best choice. God knows a car seller won't point out problems that aren't obvious or noticed by the buyer. Maybe he underestimates his credit. Maybe he would find a 10+ year old car unacceptable. If thats the case, then of course $1,500 won't buy him what he wants.
Anyone expecting the perfect car for $1500 would be delusional, or has their sights set kinda low. But it's a good place to start if you have bad credit and getting a loan would be financial suicide.