what is rocker arms on a chrysler concorde an how much does it cost to fix it on 2000 Chrysler Concorde

i live in vancouver wa 98661 i dont know what rocker arms r on a chrysler concorde 2000 im looking to buy it but dont want to unless it cost to much to fix it

Asked by for the 2000 Chrysler Concorde
what size motor is in the car?