2008 335i Coupe with 48k on the odometer.
I did a 1200 mile and 5000 mile oil change, then did oil chages @ 7500 miles at $91 dollars a piece. I had the oil tested and the result was that I could easily go 10k miles between oil changes.
I had the underbody plastic replaced after my wife dropped it off a curb, backing out of the driveway: $110.
I'm out of warranty now and I just had the oil changed, manual gearbox and rear differential fluids replaced, and the hydraulic fluid drained and filled, (and had the CDV removed while they were at it) ~$400.
I will be changing the oil once a year now, or 10k miles, whichever first.
I think my next out of pocket expense will be the shocks/springs.