I got a screaming deal on a donor truck; it should have been in the $4000 range being a 91.5 3/4T 4x4. That was three years ago and prices have been going up on the early Cummins Dodges. Great deals are easier to find when you have time. I looked for 6 months and rode 125 miles on my motorcycle to buy mine with 219k on the broken odometer. The duct tape was to keep rain out at speed, every panel was smashed (but rust free?!), the transmission needed to double clutch into 3rd, and most of the lights did whatever they wanted to do. I got the only good parts left other than the frame. In it's defense, it did have matching near-bald tires when I bought it.
My $4000 didn't even touch the transmission or axles. If I tried to do my swap today and in a rush, I would have well over $8000 (extra $2k for donor and the $2k for transmission) in my swap, not including axles and power increases. I probably wouldn't do a diesel swap at that cost, but I love the power and fuel mileage that a gasser couldn't touch in my K20.
Random note: I do want to toss an LS in a different car of mine and hopefully I can do it on the cheap, but I'll keep driving it with a traditional small block until I have all the parts on hand to do it. Keep the swap down to a few weekends (okay, a lot of weekends).