I think you should narrow down what you want in your AR
free float barrel, upgraded trigger, and what kind of upgraded trigger, handguard keymod or quad rail or standard style or other, buttstock, standard front sight or flip up, red dot or scope or prism scope or just iron sights, barrel length and heavy or not, barrel SS melonite chrome lined, etc
but I also think that you wont really know exactly what you want in an AR until you shoot it for a while and get to know what you want and what works for you
you can always modify your AR later too
have you ever thought about building your own AR? its not difficult at all.
I got my first AR over a year ago. it was the standard style front iron sight and plastic 2 piece handguard. you know, your basic AR.
it was a Core15, great rifle. also picked up 3 lowers at the same time.
in 2 months I built the 3 lowers. I built the lowers basically knowing very little about AR's. just using a youtube vid and a post from AR15.com to teach me how to build the lowers.
after building the 3 AR's I thought to myself that I don't need 4 AR's, and I sold the Core15. not that it was a bad rifle, its a great rifle. I just wanted to keep the ones that I built myself.
I see AR's online going for cheap now. Ruger AR556 going for $400-something, S&W m&p going for about the same. and other brands going for cheap too.
take your time in deciding.