probably not going to do much better than straight from the manufacturer New Frontier Armory.
I couldn''t tell you if anyone offers a better price but my first lower was from them one of their poly lowers that has held up to thousands of rounds since 2012 got that one for $99 complete with fcg stock etc. I think they are up to $119 for the complete setup now. My latest build was on one of their NV commemorative billet lowers fucking awesome lower comes with tapped rear takedown detent hole to cature the spring as well as a tapped bolt catch pin so you don't have to worry about trying to get that fucking roll pin in integral trigger guard again one less stupid roll pin and it's setup to accept a 45degree safety. Don't recall the price on that but worth every penny. Picked up a forged lower from them for my brother in laws bday xmas present think that was $79 BIL is very happy with it. Their customer service has been top notch.
Speaking of NFA Guido if you are reading this have you gotten any forward assists back in stock?