If you want something mid-way between a dealer's prices and eBay, you could try someone like alloywheelsdirect.net. I got rim damage from a really bad pothole (full of water, so invisible) on a hotel driveway last year. Hotel insurers paid for a new rim which I got through alloywheelsdirect and I managed to get the original skimmed and refurbished locally for use as a spare. It appeared to be shipped export direct from the factory in Germany, has Audi part numbers on it and was about £550, so a lot cheaper than via an Audi dealer.