$395 from DSA. Pricey, but top notch.
Adding up prices:
$395 DSA Front end
$95 DSA Complete used STG-58 lower
$40 Tapco Metric Bolt and carrier
$10 charging handle
$200 Imbel Upper receiver
+ I dunno what else
= $740 + I dunno
Hmm, suppose such a thing is worth $800 when all is said and done? I guess with such things you either love it enough to pay anything, or hate it so much you wouldn't even pay a hundred.