As of for barrel/ upper, umm idk.. Hahah like I said I'm a newbie so idk some of those things.. But barrel wise looking between 8-12 inches w/ a free floating Handguard. But if I do come accross a rifle upper I'll go for it. But I'm really trying to build my ar platform as a pistol configuration first. For legal reasons �� and yes somewhere around the price range of 300ish
Ok.. this kind of a big deal.
If you are building a pistol, you need to designate it a pistol,
and only ever have it in that configuration..
If you designate a Lower as a Pistol, and assemble it (with a Pistol buffer tube) your fine.. You can then legally purchase and own a pistol length upper.
However, If you ever assemble or reassemble it with a standard buffer tube (which yours appears to be) you cannot legally build it as a pistol EVER.
Additionally.. you cannot legally own a sub 16" configured upper without legally owning a pistol dedicated lower. Stripped (undesignated) lowers count do not count.
I have built several pistols.. and each I purposely bought a stripped lower from a FFL and had the paperwork designated PISTOL. That way if I am ever in questioned, I have the paperwork to support the legal pistol ownership.
With a %80 lower like you have, you will be on your own if you ever end up in court..
Sorry to be harsh, but I don't want you getting in trouble for a dumb mistake.