I just received a "complete lower" and a "stripped lower" today, through my FFL.

The FFL  usually only deals with CAS, so this was apparently the first AR15 stuff he'd ever seen, and wasn't much help with advice.  He was worried when my new "rifle" arrived in such a short box :)

Everything I've learned about AR15's has been from this site, and it's been great.  I've read lots of stuff, including FAQs, but I haven't seen my question answered anywhere

Anyway, I knew getting a lower was the first step, since I had to go through a dealer for it.

I'm under the impression that I can order a "complete upper" from nearly any vendor, take it out of the box, attach it with the two pins to my complete lower, and shoot it.

However, it looks to me like sometimes the bolt, bolt carrier, and/or charging handle aren't included as part of the "complete upper".  My assumption was that a "complete" one would include every part I need.

So do I need to specify, or investigate the details on all of them?  Or have I just seen some wacky ones?

And am I missing anything else important?

Here's what I got, in case the answer depends on it:
Mega complete lower with RRA 6pos stock

A "complete" upper should mean that it is complete, with bolt, carrier, charging handle, etc.... and ready to snap on and fire to a lower.

An "upper assembly" is typically the same as above, minus the B/C/CH.

That being said, not all vendors are hip.... and it ALWAYS pays to verify when making your purchase on a complete upper that it comes with everything you assume it does.  Never hurts to just simply ask.

Quoted: I'm under the impression that I can order a "complete upper" from nearly any vendor, take it out of the box, attach it with the two pins to my complete lower, and shoot it.

That is correct

However, it looks to me like sometimes the bolt, bolt carrier, and/or charging handle aren't included as part of the "complete upper".  My assumption was that a "complete" one would include every part I need.

'Complete' should have the bolt carrier group and C/H.  Do check the fine print though.

Falarak and Forest nailed it on the head.

Check out all the deals on the EE: jobrelatedstuff.com/forums/board.html?b=7

Check out the "new" uppers, parts etc: jobrelatedstuff.com/forums/forum.html?b=7&f=22

Or look for a used one from members etc: jobrelatedstuff.com/forums/forum.html?b=7&f=119

A typical complete brand new complete upper (ready to mount on your lower, lube it and fire) ranges from $450-$550, of course there are some that are quite a bit more.

Used uppers go from anywhere between $250-$500+ and up.

Bolt carrier, bolts & charging handle brand new, $115 going rate from the dealers.

Thanks, guys