I went through this the last few weeks...listen, if you really want good quality and low prices, go to Adcofirearms.com, buy an RRA upper.
RRA has good quality I'm told, and a lifetime warranty on all parts!
Here's some quick math:
RRA flatop 16" CAR or mid-length upper: $375
RRA lower parts kit: $54
Buttstock (ACE skeleton or ultra lite stock. This is just an example, any stock you prefer will do): $89
stripped lower receiver (Eagle Arms. again, example): $98
Total is $616. Note that with the flattop you will have to invest in a rear site, since flattops don't come with sights. A.R.M.S #40 is a good investment.
The above barrel is not chrome lined, but it is chrome moly. Chrome lined lasts a lot longer than other barrels. Below is another option:
Model 1 CAR kit (includes everything besides reveicer): $415, or $450 chrome lined. Go for chrome lined!
Eagle Arms lower: $98
Total is $513 or $548 chrome lined. Again, go chrome if you can, it is well worth it.
However, Model 1 has no warranty, and again if you get a flattop you would have to invest in a good backup sight unless you are just gonna slap an EOtech or Aimpoint on it. Another option is a removable carry handle, which they offer for an additional $75. I would just buy an ARMS #40, because it is a flip up sight and you can use it AND optics at the same time, or if your optic dies or something, you can just flip the rear sight up and use the irons.
Can you tell I've been planning to buy one?
If I were you, I would order the chrome lined kit from Model 1 or similar company that offers a good kit and buylower, assemble it (instructions can be found on AR15.com, its pretty easy to do) and enjoy your rifle for a good $200 lower than just buying a complete one. Not to mention the sense of accomplishment
edited to add: Also, the free float tubes heat up alot, so plinking is not good with them. They are more for sniper-type ARs, competition shooting, or varminting. Nothing against them, but I would rather not half to wait 10 minutes at the range for my handguards to cool down...
just my $.02
Sites to check:
www.adcofirearms.com
www.model1sales.com (sells kits)
www.quanticoarms.com
www.rockriverarms.com
www.m-aparts.com (sells kits)
www.jtdistributing.com (sells kits)
and, of course,
www.ar15.com