Palmetto State Armory (PSA) is offering their "M4A1" with Aimpoint PRO for $999! This is an awesome setup and an amazing price--perfect for new shooters or someone looking to pickup a carbine.
The only thing I don't like is the BUIS and the buffer spring (black v. chrome). These can be easily remedied!
The PRO itself is a $400 optic. I was lucky to be able to pick one up on discount for around $375. The mount screw is a little bulky but it doesn't bother me.
Couple of other things I like about this setup... Barrel is Cold Hammer Forged (CHF), which produces more accurate barrels, and is made by Fabrique Nationale (FN) in South Carolina. FN is a major defense contractor and has been making M16s and M4s for the services for many years. I was once issued a FN M16A2 a long, long time ago. Bolt and BCG specs are also impressive.
PSA has also made this setup as close to mil-spec as a civie can get. Folks who go mil-spec recognize the massive resources that have gone into finding the most reliable parts and manufacturing processes. For purists: this is a 16" barrel not the 14.5" that can be found on the real M4. This also means the carbine can be purchased without NFA entanglements.
PSA's lowers are no-frills and top notch. The lower I have mated up with a Daniel Defense upper with less play than my factory Colt 6920. All lower parts were in spec and assembly was easy.
Here is a pic of the PSA/DD build I completed earlier in the year...