what is the cost to replace the oil pressure sending unit on 2001 Pontiac Bonneville

My oil pressure gauge floats back and forth. Oil level is OK

If the gauge is responding to changes in engine RPM you should get the pressure checked with a manual gauge.oil pressure is different from volume .you can be low on oil and still have good pressure if the engine is mechanically sound.Depending on the shops labor rate --1hr.labor and about$25.00-$35.00 for part