So today I was looking at AR's and what I found around my area are these

Stag Model 2 NEW for $850
RRA Entry NEW for $899
Colt HBAR 20" used for $925

I don't know a whole lot obout AR15's and instead of having questions I would like to know what you guys think of these choices/prices. And if you say for this price you could build one. Well what is a good upper and lower to purchase...... I usuall like to buy pistols when I come across good deal but now really sure what is good in the AR arena. I was looking for under $900.