$500 for all 4 is nuts.

Amazon has them for about $46 each and most tire shops should only charge about $20 per corner to install them for you.

https://www.amazon.com/ACDelco-13598771-Original-Equipment-Monitoring/dp/B01E6EQV1W/ref=sr_1_3?keywords=ACDelco+13598771&qid=1564676862&s=gateway&sr=8-3