Funny, I wouldn't recommend any of those, but to each his own.Lots of good info in here. I agree with @dennishoddy no reason to waste money on a built lower. You can build a lower at your table with a youtube video in an hour you will need a few tools that can be found inexpensive on Ebay an armorers wrench and a vice block and some punches. Thats the best place to start if you want to build an AR. Get a lower then piece it together they way you want it.
If you just want an upper and lower to put together. I still would suggest going with a built gun if your not wanting to build the whole thing. New gun in box will have been tested with all parts together. Head spaced and have warranty. I know PSA has warranty and tests their uppers but not necessarily with the bcg you are buying.
Also if your in Duncan its worth a call to Lawton Academy to see what ARs they have in stock or can order in. I wouldn't have an issue with any of these
Ruger $649
https://www.academy.com/shop/pdp/ruger-ar-556-556-semiautomatic-rifle#repChildCatid=1364736
Sig $799
https://www.academy.com/shop/pdp/si...rem-semiautomatic-rifle#repChildCatid=6787008
SA Saint $849
https://www.academy.com/shop/pdp/sp...ato-semiautomatic-rifle#repChildCatid=3891145
If those are out of your price range. Check atwoods they usually have some less expensive stuff.