Thom is right. You can get a used AHK for a fraction of the price on ebay and even cheaper from different sources.
Depending on where you live it could cost a small fortune to deliver an AHK. As they are quite heavy.
So where do you live? And have you checked some of the ebay sellers like BMWgebrauchtteilehamburg or
www.gebrauchtee32teile.de ?