Thanks to Postell, kyleb350, DrivenByE30, and aajami for answering. I really appreciate it.
Right now I hope to start out with a used 5-series for around $10-12K.
I'm a total newbie, but I'm researching and hoping to learn more. Where's a good place to check out the side-by-side differences between the 528i, 530i, 535i, 545i, 550i, etc.?
And let's say I purchased an older (2003 on) model that doesn't come with any warranties. Approximately how much more can I expect for maintenance than the practical cars I've had before (I know this probably varies widely, but ballpark figure).