If you need gears or a Sure-Grip for your rear, Jeep Cherokees, early Dakotas, and even some half ton trucks and vans commonly had decent gears and Sure-Grips in them, and can be sourced pretty cheaply from the boneyard.
Just be aware that the axle spline count changed in the mid/late nineties at some point, so you need to stay with the early versions.