I bought a 2011 335d in April of this year for $10,700. It's Space Grey with black standard leather, has Navigation, convenience, premium, cold weather packages, comfort access, rear and side window shades. Had 68k. The dealer I purchased from had bought the car at auction in May 2018, with 64k, for $14,000. I have the paperwork. He admitted to taking the loss.
The values on these seem to fluctuate, and they depreciate kind of unsteadily. I bought a 2011 E93 335i M-Sport, loaded with literally every option except Adaptive Cruise, in February of 2017, with 55k, for $23,000. I drove it until this past December, to 92k. It needed a water pump, but wasn't readily apparent at trade. My husband was dead set on a Subaru Forester XT, so being a great guy I signed my black beauty over to the dealer for a paltry $7500. Like an idiot. But it is done and over with now. They sold it in 6 days, still needing a water pump, for $12,500.
The guy that bought it traded it about a month ago at a dealer, owned by same parent company, close to our house, and I spotted it from a distance. Looked up vin and sure enough it was my car. The water pump was replaced, and they sold it for $16,500, now with 99k. So plenty was made on it, just not by me.
For what its worth.