Any help planning a build that will be cost effecive ?

Hey i appreciate all of this info i havent thought of doing the swap like this before but it seems like it would save me quite a bit of money thanks again for the post
No worries! Again, this is how I plan on doing mine. If you choose this route, just be wary of buying vehicles from the auction lot, as you're gonna have to be a bit patient to find the right one. So far, the main variables that I have had to consider are:
1. Damage area. Try to avoid vehicles that have heavy (like, major serious) frontal damage. It may bit a bit too wary, but heavy frontal damage could mean a damaged motor or radiator or what have you. If there isn't too much intrusion in the engine compartment (local Copart auction often post pictures of engine bay), then it will probably be okay. So far I have gravitated to vehicles with side or rear damage.
2. Rollover. Be careful of rollover vehicles. Usually a rollover (esp. severe) means some amount of oil starvation to the engine for a brief period of time, especially if the vehicle sat on its roof. You have no way of knowing the specifics of a particular vehicle, so it's better to just not risk it with a rollover vehicle.
3. Damage extend. You want to find something that is juuust wrecked enough for your purposes. Often times, vehicles with light damage will be purchased by individuals who then repair and flip them, or simply part them out. On the other end of the spectrum, you probably won't want to buy something that is so destroyed that the only tool suitable for disassembly is a sawsall and a plasma torch. Try to find something that can't be easily put back together, but won't be rocket surgery to take apart :)
4. Finally, mileage. You probably won't want a 220,000 mile engine in your car. Again, this is difficult to be picky about. You don't know how well the vehicle was maintained, etc. Personally, I try to find stuff in the 120k range, and I usually stop looking past ~175k miles.

Anyways, this is just one of the other options to consider. It was my first though because living in Alaska means very few junkyards or pick-n-pulls, and very expensive shipping. It also means a large truck population. Toss in a little bit of winter driving conditions, and presto... a plethora of Hemi Rams and Durangos that have been wrecked by poor driving or misfortune...