I got a new key via Audi last year (July 2016) for around £200 ish for my 2014 A3. Might have been more. I bought my car 2nd hand with only 1key. I was warned off going via a 3rd party key provider. The car had to go in to Audi for around 30mins whilst they coded the car to the key. I was offered a key via a car key service provider, forget the name, but they told me that no one provides the service where it can disable the alarm or have the transponder working. It will only work in the key barrel, which really makes it useless. Technology might have changed now. It I would be wary as I think Audi have to connect to the main system in Germany to pair the car via a 1 tone only code. If you search my threads on my profile then you will see the question I asked and responses I received, all which told me to only go via Audi.