You didn't say what you wanted from the rifle so I'm not going to assume but just post what I'm building right now. Prices do not include shipping. Also, Green Mountain charges sales tax on their barrels no matter where you live. Some of these were caught on sale. I would have ordered a FN barrel had I found them in stock at the time.
PSA blem lower $60
Surplus A2 stripped upper with rear sight $85
Green Mountain 20" A2 5.56mm 1:7" barrel $160
PSA A2 butt stock kit with LPK $99
BCM BCG $159
A2 rifle handgaurds $18
Handgaurd cap free from LGS
PSA upper build kit $35
Parts for FSB $12
Pin on FSB by Adco $111
A2 flash hider $10
Gas tube and roll pin $11
BCM Gunfighter charging handle $50
I think that's all of the parts. Total of $845. Keep in mind that doesn't include shipping charges for all of the orders which would probably add on $80 or so.
If buying a stripped barrel, don't forget to factor in the cost of a FSB and having it pinned on. For a strictly range gun, I'd be fine with a set screw or clamp on FSB or gas block. When I build a 3 gun rifle it will likely have a clamp on gas block because I'll use an optic and offset irons. Won't be counting on that rifle for my life, though. For a rifle I might use in a defensive situation, I'd rather have a FSB taper pinned on. If your FSB comes loose you no longer have a good front sight and your rifle becomes a single shot as you'd have to charge each round. I understand most gunsmiths don't have the tools and fixtures to do this. Adco comes recommended for this service and charges $111 if you supply the FSB. Once you add in the cost of the FSB and having it pinned on with shipping both ways, buying a barrel assembly instead of a stripped barrel becomes pretty attractive.
Watch for PSA to have their blemished stripped lowers and uppers in stock. $60 and $50 respectively is pretty damn cheap. I bought four lowers and a couple uppers.