While my personal loyalties are with Armalite, there are a myriad of manufacturers out there right now making equal quality rifles. With the availability of components nowadays, probably the best rifle for the $$ would be one you assemble for yourself if you're willing to invest the time to do so.
I agree. I have a Colt target model, iron sights, that I bought in 1995 and a Bushmaster m-4 flat top that I bought 3 years ago. Both are excellent weapons and the Bushmaster is suprisingly accurate for a carbine. You can’t go wrong with Bush or DPMS or Colt and you’ll still have money left over for some decent optics.
The new sheriff in town is Stag Arms; specifically the Stag Model 3.
Buy a flattop from CMMG, Spikes Tactical or one of many good sources.
Spend maybe $800..... use the rest for a decent red dot optic and P Mags.