2001 Chevy Impala Cost of MAF & fuel regulator replace?

My Impala was starting hard and occasionally dying on the road. No codes. The dealer said it was the MAF and fuel pressure regulator. They wanted over $750 to do the repair. I paid them $80 for the diagnosis and took the car home. I bought the parts from a auto parts store for $200. The removed regulator did not have a leaky diaphragm, but replacing it cured the problems. I removed inspected the MAF but didn't install the new one. These parts are very easy to replace in just a few minutes. After returning the MAF my end cost for the fix was $130, $50 for the regulator and $80 for the diagnosis.
Was my dealer being fare with that $750 price?