Heres my understanding of the 3 metal shafts on the heli.
1) Main Shaft. This is the vertical shaft, 3mm, has a big gear on the end driven by the motor.
2) Feathering Shaft. Metal horizontal shaft that connects the bladegrips through the head.
3) Flybar. The small metal bar on the top of the head that connects the small plastic paddles.

I think the flybar is the only one that has a consistent name. I've seen lots of other names/descriptions for the first 2.

Most pricing is about the same online. Sure, some have for a few cents less here and there, sometimes more. It really comes down to service and shipping. I like willstech.com, they are extremely fast at shipping the order, most times same day. Charge actual shipping cost (4.05 for USPS Priority mail, 1-3 days continental US), and a stated up front 1.50 handling. I dont mind the 1.50 handling, as they tell you upfront, and they sure earn it with there level of service.

Sure I can drive across town to the LHS, but for the 5.55 total for shipping and handling, its not worth the gas, time or traffic. Washington DC sucks on traffic,I'm sure as most everywhere else.

Hobby-estore.com = Sucks
China (rc-expert) = Sucks (service wise, and for sending u incomplete parts, but the $20 3s 1200mah lipo worked out good)
Hobby4less = Mixed results (but thats for DF#4 stuff)
HeliHobby = Ok in my experience, but others had had mixed results
HorizonHobby = OK. good service so far
Wholesaletrains.com (yes, they have CP parts), OK so far
willstech.com = My favorite. Its only 1 (sometimes 2) day shipping for me.

I usually buy enough in advance, so that the 2 days wont kill me.

Then again, if i absolutely, positively have to have it the same day, and the LHS has it, i'll brave the traffic.

crashn_bernstein (only the crashes are more spectacular and more devistating now that i can somewhat fly around)