Cost for free standing 2 car garage

[Tom.A]

I was wondering if any of you home builders in California can give an idea what to expect in terms of cost to build a free standing 2 car garage. I have been looking at buying a neW home and we found one that my wife and I really like except they only built it with a two car garage. The price of the home is kinda at the limit of comfort zone so the add on would have to be at a later time. I thought about a metal prefab but would much rather have it match the house which as cement style siding. Is it a big Pita for permits also?