in junkyards, expect $800-$1000 for a complete dana 60, with brakes, tierod, hubs, etc. it will most likely need a rebuild.
also, you can use a dana 60 from a Dodge, they are very similar to GM dana 60's...that is what I am going to do.
check
www.pirate4x4.com , there are articles on the dana 60 and 14 bolt there. lots of good info.