Hi folks,
My memory somehow told me that this had been discussed not long ago here, so for those who might be interested.
The right heated mirror stopped working on my 09/1999 A6 Avant. I had it replaced at my preferred Audi dealer and the total cost was 49 Euro (~60 USD) including parts, working time and tax. The part cost in that sum was 33 Euro (~40 USD).
As opposes to the usual rumors of extremely expensive Audi parts I personally think that's not that much.
Regards
Wolfgang