How much is the air pump repair? - Code P0410

I've seen it talked about, but I haven't seen an estimate? How much is the repair usually done for a P0410 code on the service engine soon light? It's the "malfunction exists in the secondary air injection system" code.

GM tech notes say it is usually the air pump below the radiator which needs to be replaced. Well, haven't had any problems. Just want to know if it is something worth the $100 deductible on my extended warranty.

Thanks-

Just got this failure on my '01 blazer two weeks after the warranty expired.
My mechanic tells me that the pump is about a $300.00 repair, all this just to turn the service engine light off.
There is a fuse that controls this system and it was suggested by the dealer and my mechanic to check this first, but I can't find out which one it is.
Apparantly water gets into the pump and causes the problem. Good old GM engineering at its finest.
This is all I know so far, I will let you know what my outcome when this is resolved.
I am tempted to sell this vechicle after this is fixed.
Disgusted with second rate american automotive enginering.
JJG