Where can you get a good M4 type Complete upper with B/BC/Ch for under $400?    Anywhere?

Unless you buy used, having the B/BC/CH included will not get you anywhere near that price range.  $450 maybe, but $500 is about what you will expect to pay for an upper with everything.

Much higher than that (about double) if you  want a genuine Colt M4 upper. You might find an aftermarket upper used or minus B/C/CH as mentioned above for around $450-500. Are you after the M4 barrel profile or do you specifically want the other feature (feedramps) of an M4 receiver? Even then, you could get an aftermarket upper machined with the feedramps for less than the cost of a Colt piece.

Choices, choices....   It all depends on what you want.

Ah let me refrase then I a complete upper with 16" barrel and brake.    

I am thinking after market as I already have a complete colt.

What is the difference between a brake and a Flash hidder.  Will it matter in September?

Look in the EE.

Got a complet flat top upper with a 16" Bushie barrel with RRA enhanced carrier,M4 handguards from eagle firearms.net $442 shipped no removable handle..already had one..regular A2 is $506 shipped.