Cheapest place for a spare key?

[ainarssems]

The main issue you have is that (allegedly) the immobiliser chip can't be coded twice so if you see a complete key with new blade and immobiliser chip it'll do the job once coded by a specialist or one of the folk on here if there's someone local with the required kit

It's the car that is being coded to accept immobiliser transponder in the key not the key. Dealer kit goes online to retrieve login PIN to code key to the car and if the transponder is in database as used before on another car it will not allow to use it. Third party solutions reverse engineer login PIN from car without going online to Audi servers and does not care if it has been used before oe even know if it has been used.