my oil shot to 80 oil pump went out.Can someone give minimum price to fix. on 2001 Chevrolet Blazer

Ran fine day before, have noticed be4 this happened oil pressure carrying low at idle. Went 2 start and pressure shot to 80.

Asked by for the 2001 Chevrolet Blazer
have you done manual oil pressure test to se if gauge is bad 1st
Most likely sending unit if this is the only guage acting up.
the Mechanic says it is the sensor on the oil pump so gonna replace oil pump. The pressure has been carrying about 30 at idle a couple of weeks before this happened. when driving it was about 50-55lbs. then shot up to 80 and lost oil out of oil pan trying to go to mechanics. So hopefully not to expensive!!!!!