I got my '97 328is 5-speed with 91k miles for $8800....and that was from an Infinity dealer. I had to pay $900 for tax, title, and license.
A very well driven 328is 5-speed can do 0-60 in less than 6.5 seconds.
If you search hard enough and don't mind a high mileage car you could get a '95 M3 for around $9000. They have 240 hp and can do 0-60 in under 6.0 seconds