I broke my driver side rear mirror. Does anyone know how to replace it? and how much does it cost to buy a new one? Thanks a million!

 

get the OEM from Nissan. You want a mirror that fits perfectly into your mounting bracket behind the dome/map light.

If you don't mind sticking your mirror to the windshield (like American cars), then go with aftermarket auto-dimming mirrors with your choice of compass/temperature/map lights for less than $200.

2 companies make 'em:
http://www.donnellye.com
http://www.cipamirrors.com

Good Luck with that!