What's a good deal for a 2000 3 series?

I am asking this on behalf of someone.  I've never bought a new car before so
I don't know the answer....

What is considered a good deal for a year 2000 328 coupe?  I know how to
figure out the dealer invoice prices, but how much can you negotiate down to?
$500 above invoice? $1000?

Thanks much.  Maybe I can use the info for myself one day :-)

- -K Chan
'89 325i, runs great.. .needs rounder wheels

------------------------------