14-bolt = $100 from the local junkyard, welded diff = free, disc brakes = about $100 for brackets and line, had rotor and calipers off the old 10-bolt, about $75 for u-bolts and a few other misc. items
D60 = $750 for a running (but completely rusted body) K30, $350 Lock-rite, about $300 in u-bolts, calipers, u-joints, etc... to make it work. The plan was to sell the rest of the drivetrain from the K30 (350, SM465/205, 14-bolt) to recoup some cost...but I won't go there on what happened.
So maybe $1,700 for a set of 1-tons with lockers and disc brakes. Already had tires and wheels.
I have upgraded over the years, but none of this stuff is required to go off-road. 35-spline stubs and flanges, cross-over steering, hydro-assist, heavier tie rod on the front. I did rebuild the rear with new bearings (forget, but maybe $150 for kit) and installed a pinion guard.