2001 Altima Valve Cover Gasket

Hi,

My 2001 Altima's Valve Cover Gasket needs replacement. I had it checked by the nissan dealer and they gave me estimate of around $250. To get the second opinion I got estimate from a local mechanic and he told me that it would be done in around $100.

I am now confused. Does anyone know how much is the normal charge for changing the Valve Gasket Cover?

I checked the price of the valve cover gasket on the autozone and advanced auto parts and I found that they are $24 and $54 respectively. Can you please let me if I am searching a wrong product?

Thanks for your help in advance...