I built my first FAL for about $800. I was able to find a gunsmith on the FAL Files who was willing to mentor me and let me use his tool. This was a big help because the cost of tools would have added another $200. He also helped me make sure everything was assembled correctly and it was properly head-spaced. We even sand-blasted and parkerized it so it looked like a brand new rifle. It functions flawlessly and I would put it up against any new or used FAL that I have seen for $800.
I would definately suggest joining the FALFiles and ask for any builders in you area who are willing to help. I just finished my second FAL (a para cabine approx. $1000). I built this one mostly by myself and I had a couple more hiccups from not having an experienced builder with me. I still got the rifle built and it seemed to work fine when I test fired it last weekend.
Building a FAL is closer to working on a car than gunsmithing, everything bolts together with a minimum of fitting and requires only two or three specialized tools. Do the research on the internet, ask around the FALFiles, and you should have any problems.
Edit: Both of the kits I got came with nice barrels, my 21" FAL has no problem hitting a 12" taget at 100 with the stock iron sight. A replacment barrel can run you $70 (for a converted Rem 700) to $250 (for a new DSA chrome-molly).