>>627319
Building an ar is piss easy, just get an armorers wrench, upper and lower receiver vise blocks, and some anti seize grease for the barrel nut threads+barrel extension. That should be all the specialized tools you need.
There are a few parts you should not cheap out on
>barrel
I reccomend faxon barrels, just make sure the barrel is either chrome lined or melonited/nitrided and is made from 4150 or 4140 chrome moly steel. Or you could get a stainless barrel. Ive also had good experiences with PSA.
>BCG
PSA makes fine stuff, toolcraft and brownells also have quality bcg's.
>optic/sights
Many budget red dots these days are pretty good, so a holosun, vortex, or sightmark wolverine would probably be fine. If you want a magnified optic vortex has a good selection, and i've heard good things about primary arms. For sights, you can't go wrong with the magpul buis.
Everything else should be reputable but cheap, mil spec or magpul furniture is good, cheap quad rails, mil spec triggers are fine, get the CHEAPEST recievers you can. Check the black friday thread, there are anderson lowers for $40, A2 flash hiders are great and very cheap.