I just did that. It cost about $380 for all the parts and $120 for the dealer to install them. It is DIY, but I didn't have the time prior to a road trip and switching to non-RFT winter tires. You will have to get the tire mounted to the rim.

The $380 includes the wheel, an un-mounted tire, a tray, the HW to secure it to the tray, a jack, and a lug wrench. The local parts guru ordered it all but the guy behind the counter when I picked it up had no clue about it, or where the other guy had put it. I said isn't that tire, and large box over in the corner, the kit?
It still took him 10 minutes to ring it up....

__________________
Richard
Sir Snaps-a-lot, 9 Time Dragon Slayer (54 runs!)
2011 X5 50i Alpine White, Biege Nappa /Lt Poplar M Sport
2009 Z4 35i, Black Sapphire/Ivory-Black/Anthracite

Gone but not forgotten: '08 550i, '06 X3, '06 650i, '02 M5, '99 540i