For fronts, anywhere from $250-450.
Parts alone, depending on quality of parts, $100-150.
I think my e36, the parts costed me:
1. $75 (for both front rotors; generic rotors)
2. $45 (Pads; high quality, Wagner)
3. $8 (Hardware; Wagner)
4. $15 (Brake Sensors; from BMW dealer)
Took maybe an hour, if that.
Good luck.