How much should an amplifier cost? on 2006 BMW 330xi

After a big rain storm, we started the car and the speakers made a fuzzy crackling sound and then stopped working. The dealership said the amplifier needs to be replaced. I am wondering if this is the most likely diagnosis, and how much it should cost. They said the part is very expensive but the labor is not much.

Asked by for the 2006 BMW 330xi
It is very possible because of the location of that amplifier. The part is about $1200.00 if the car was produced before 09/06 and it has a Harmon/Kardon stereo system. I hope this helps.
I purchased mine for 100.00
Where did u buy it for $100? Dealer quoted $2k for repair. Thanks in advance