Here's a stripped receiver also... re-use all of your other internal parts from the old upper, slap on the new barrel, and you're good to go. Probably take you about 5hrs to do the rebuild if you get a book to follow along with. I can build one a lot faster, but I've done a few.

http://www.midwayusa.com/viewProduct...tNumber=589236

$125 for the receiver, $200 for a barrel, $8 for pins, and a rainy saturday and you're good to go...