O-ring replacement on 1997 Nissan Maxima

I have a oil leak i took took it to a mechanic he told me the O-ring needs to be replace, how much would it cost me to replace it?

2 answers 2 comments
which o ring? to reseal what
i believe its the water pump and another where the water drain plug is located...
based on what your telling me repl the water pump and radiator drain o ring the cost is approx 600.00 parts and labor
Was it an oil leak or coolant leak being fixed?