MacCool

I buy virtually all my ammo from them. Reliable, fast shipping, good customer service. They have a good reputation. If you're looking to buy a stripped lower, they are a reasonable choice.

If you're going to assemble the lower, I would price out the parts individually and compare them to this complete lower. I would order that lower with the MOE trigger guard, the MOE grip and the CTR stock, and I would also add the Noveske QD endplate so you have something to attach your QD sling swivel to. The blemishes on those BCM cosmetic blems are notoriously minor.

Or, I would order a cosmetic blem lower from BCM without stock body and add a CTR stock. That setup would be a better deal.

The advantage to buying an assembled lower is that you wouldn't need to buy any of the special tools that facilitate such a project. To assemble a lower, you'd need/want a set of roll pin punches, a set of regular punches, an AR castle nut wrench, and a mag well vise block. Other really useful tools would be a bolt-release roll pin punch (avoids marring the receiver) and a pivot spring insertion tool (getting that pivot spring/detent/pin in there can be a bitch...I've launched many detent springs across the room over the years).

Bottom line, first you need to decide and price out assembly of a stripped lower vs buying an assembled lower. If you decide on assembling it yourself, the options for stripped lowers are dizzying. And, it's kind of a minefield. I would have little concern about a stripped lower from Palmetto State Armory. On the other end, I would avoid, like the plague, buying a stripped lower from some guy at a table at a gun show.