Question
Ballpark estimate, about how much might it cost to have a nice garden installed, with maybe 5 fruit trees and a vegetable patch, enclosed by some nice stonework,  and a fire pit and seating area? (in Orange County, California)

Answer
I am not familiar with your local labor rates, however in the southeast this would likely cost between $7000 and $10,000.
But that is really a guess as your description is pretty vague.

I hope that helps.

Sean J Murphy, ISA, RLA, LEED AP
Please check out my landscape focused websites at:

http://www.seanjmurphy.com
http://www.amenityarchitects.com