About the only bike you could buy new for what you want to spend would be a 750 Shadow. Now, if you wanted to buy a slightly used bike. You could go easily find bikes from 600 all the way to 1800's for $6500.
What kind of riding do you want to do? Do you want to commute to work, tour, cruise, motocross, or? That answer will help steer in the right bike choice direction. Honda makes great, well priced bikes for all kinds of riding, just decide what you want to do.