04 Tahoe LT with Autoride

[WhiteWarWagon]

My dad has an 04 equipped with the autoride feature and because I am off at school he took it in to a mechanic for some servicing. According to the mechanic the autoride compressor is bad and also one of the air ride shocks. Its about 500 dollars a piece! Local part stores are around the same price!! Im just wondering if anybody has experience with this failure before or have any idea where to get something a bit cheaper, I cannot believe that price!
all input is appreciated

 

[Sasquatch]

A few guys here have used this place with good reviews of what they sell. https://www.arnottindustries.com/part_GMC_Air_Suspension_Parts_yid15_pid95.html