I just saw this at Brownells. A .338 Federal Marked Stripped Lower for $109. This can be used for a 308AR and is a great price.
338 Federal 308AR Stripped Lower Receiver – Rugged, fully machined 338 lower is ready to be the foundation of a hard-hitting long-range tactical, competition, or hunting rifle built to meet your exact specifications. Precision milled from a solid billet of high-grade 7029 T6 aluminum, with extra metal in the right places to handle thousands of rounds of full-power ammo without flexing or stress-cracking. Mil-spec hardcoat anodized for extra surface strength and corrosion resistance. Beveled mag well aids in fast reloads, and the integral, straight triggerguard milled from the billet with the rest of the receiver provides clearance for a gloved trigger finger while adding to the structural strength of the receiver.
Accepts standard 308-AR upper receivers & components.