Always lowball the dealer.
My 2010 335i sedan was a CPO originally listed at $35,995 with an 'Internet Discount' that brought it to $33,995. KBB had it listed at $35,983.
I ended up getting them down to $31,500. Car has almost every option you could put on it.
I originally offered them $29,500 for it and they kept going back and forth with me. They didn't dismiss my offer at all, they came back with a counter and so on.
2010 Alpine White 335i
- Sports Package, Premium Package, Navigation, Comfort Access