A bit of both. There's a whole lot of unfamiliar terms. I suppose my first question for you is what you want to do with it(just to have one, occasional plinking, long range accuracy, competition).
The main point is that due to the nature of ARs all being restricted by accident of birth, there's not much point for the average person to spend huge amounts of money on it.
Granted, there are some very fine guns available for, say $1600, but they're not going to really give you any appreciable difference on a casual basis. A $600 norinco will do you fine for the occasional shoot, it's when you start doing competitions and courses and all that jazz that the fancier guns start to apply.
Unlike most other firearms, the AR platform is completely modular. The vast majority of brands out there work with one another, so you can start off with a $600 norinco, and end up with a $6000 superpowered custom gun that can fight off alien invasions, all one piece at a time.
It's a completely different perspective from other guns, where if you buy a cheap entry level gun you're stuck with that gun and can only modify it within a narrow spectrum such as trigger pull, unless you pony up massive amounts of money for a gunsmith to replace the barrel or something. With an AR, you can swap components very quickly without specialized tools in most circumstances. That's maybe not a huge consideration for the average guy, but it really comes in handy for competitive shooting as you can easily carry a kit of spare parts to replace any springs, pins, or other minor components rather than needing to send it in to a gunsmith for repairs.
There are some good videos on youtube, such as
http://www.youtube.com/watch?v=hgcpR2QYBSY&feature=related
Or
http://www.youtube.com/watch?v=PFFN_j3WD80&feature=related
I really don't know where to start for general explanations, other than to say that an AR is a collection of parts, whereas most other guns are complete units. Youtube has some very good videos if you look around. If you have specific questions, don't hesitate to ask.