during the panic SARCO had stripped a3 flat tops for $59 shipped --those are gone.
the best i can find is SMG has a3 flat top uppers for $80 on back order to ship the 21 jan-- jan 21 ain't that far off sooo---
everybody is out and their going to be retail price at least --if not more when they come back in stock--
16 Inch M4 - Style Barrel - 606333, Barrels at Sportsman's Guide you can search for the upper off this m4 barrel link
other than that JSE may get some --they will be about the same price as SMG when they get a new batch--