The right upper?

[A5BLASTER]

Build it yourself will always be my answer.

Cheap harbor freight vice
Magpul bev block or a simple clam shell for holding it in the vice a few Allen keys for small screw in gas block, small crescent for muzzle device and tekton torque wrench and correct size crows foot wrench for the barrel nut.

Joebobs parts as follows
Matrix upper add the joebobs forward assist, charging handle and port door kit- 75 bucks

Also joebobs parts fireing pin, firing pin retaining pin and cam pin 20 bucks

Also joebobs Matrix hanguard of your choosing just short enough to not cover the gas block.

Gas block cheapest adjustable block they have in stock joebobs add joebobs gas tube 80 bucks for block and tube

Joebobs muzzle device of your choosing in 30 cal threaded 5/8x24

This fourm 20 inch group buy barrel

Maxim firearms for the bolt 80 bucks

Right to bear arms stripped lowmass bcg to complete the upper.

Should be in the 500 buck ball park for complete upper you built yourself.

Now that's doing it on the cheap can go much higher depending on parts selection.

Hope this helps sir.