I just did this, however, I simply got a 79 k10 frame and swapped bodies. However, for the individual parts, the local salvage yard- U Wrench It, says this for prices
Engine- 79.95 plus a 35.00 core
Trans- 79.00 plus a 20.00 core
t-case- 40.00 plus 10.00 core
crossmember- don't know (maybe 20.00)
differential assembly- 170.00 with core
springs- maybe 20.00 each