Price depends on many factors. Typically you can find a D60 for about $800-1500 which may need to be rebuilt. If your like me and find out that the 91-94 ball joint axles had slide pin calipers and smaller rotors after buying the axle then you can throw in another few hundred dollars for brakes. Mounting the axle can be as simple as bolting it up to the TTB leaf springs but it will ride like crap. A better method is spending $300-400 for a RSK that uses SD springs. This will lift the truck some and give you a much better ride but will also need new springs $100-300 used or new. You will also want a new pitman arm $100 so you can fully turn the axle side to side. You may need to lift the rear to match the front, $100 for blocks, more for springs. You also need miscellaneous stuff like U bolts, alignment, the driver side ubolt plate.
Once the axle is ready to go, you can have it under the truck in a weekend.