Fuel Pump?

This post is a little off topic, but since I know there are some very
knowledgable people here, and I'm here anyway, here goes.
My G/Fs 2000 Cavalier wouldn't start the other day. It'd turn over just
fine for a second or two then it'd sound real rough as it was turning
over. You could actually see the engine rocking slightly when it was
sounding rough. Tried it an hour later and it started just fine, and
has been starting ever since.
Well, I sure ain't no mechanic, but it seemed like an electrical or
timing thing to me.
She took it to a real mechanic(hopefully), and he checked it out and
said it was the fuel pump. He has one on order. Gonna be $500. total
for the job. Does this diagnosis and price sound right?

abot 200 to 390 for the fuel pump