Do some reading if you are new to the M14 bandwagon. Learn to identify USGI parts and start to get a feel for the parts' individual prices. I am in the process of collecting components for (2) new M14 projects, and they are expensive, especially if you covet the ever elusive NEW grade of component. YMMV.
Op-rods are $150.
Stripped bolts can run $130.
Flash hiders are $100+.
Gas cylinders are $100-$120.
Gas systems, complete with cylinder, piston, lock, and plug are $150+.
Trigger groups are $70-$120, depending on manufacturer.
Receiver, $500-$700.
USGI Presentation grade stock from Fred's, $125.
USGI barrel, $250+. (used)
USGI barrels in NEW condition are hard enough to find that many people are getting new commercial barrels from Krieger, Criterion, Shilen, Douglas, Hart, and Obermeyer. These are all fantastic barrels for competition, mind you, but they don't do much for authenticity of an M14 project.
Visit the Fulton Armory FAQ, then do Google searches on M14. There is a lot to know.