www.repairpal.com/estimator
Check that link for the Estimator tool on RepairPal.
If the component is not listed there, you may have to consult some local shops for a "real world" estimate --
www.repairpal.com/repair-shops
RepairPal Certified shops can diagnose and repair your 2013 Mercedes-Benz CLS550. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.