On Thu, 22 Feb 2018 20:44:53 -0800 (PST), Its Me
wrote:

A basic "starter kit" AR is $400-500. You have to assemble it (the lower). A good assembled AR is about $1000.

Building one is easy. Once you've done it, you can build a lower in ~20 minutes. The upper, if you have the couple of tools required, shouldn't take more than that.

Rural King will sell you a S&W M&P for $500 ready to go, no assembly
necessary. I even see them less on sale occasionally.