sports mans guide has a shipment of the ess 16" m4 barrels for $89 for club members, 1-7" twist stripped.
you can get a discount code and get $10 or more off--
they got one nice code where you get free shipping and a $20 gift card over at "retail me not" you'll have to hunt around over there and see what cooking on the discount codes.
i think the one i ordered came out to $92 shipped.
be aware i have not shot this barrel --but ESS is not "hated" by anyone i know and the gas ports are known to run small. i think they make a decent budget barrel.
16 Inch M4 - Style Barrel - 606333, Barrels at Sportsman's Guide