I bought one of the $75 Apex Arms take off barrels that were talked about in one of the threads
$6 EE USGI FSB
$5 set of aftermarket hand guards off EE
New aftermarket bird cage and washer ($10)
The aftermarket upper assembly, charging handle, delta ring, and the complete BCG were off a complete upper I bought a while back and striped. ($250)
The A2 lower was a complete Stage Arms unit currently not being used. ($170 including LPC)
The complete butt stock is NOS USGI ($20 off EE new in the bag).
Buffer, spring and .750 triangle end cap $20 used
Buffer tub came out of an A1 parts kit I believe and was on the lower already
Spacer and screw, new aftermarket ($9)
I just ordered a black silent sling off eBay for $6.
Total for the build $571
I could have done better if I shopped and used the PIF thread on retro (free!), but it is not too bad. Out of pocket this time around $146