I'm doing it right now starting with no electronics you just need to shop around and be willing to do home work. Let me lay it out a bit here. The harness will cost you but you can find one for cheap if you are willing to dig around. I got my Harness from 5.7hemi here on fabo for cheap, my pcm was 100 bucks used, a used predator on ebay will run you about 300 bucks and most cmr tuners will work for 250 on an email basis which would get you running. A full cmr dyno tune will run you around 3-500 if you have made changes internally like a cam or heads and some will even update your tune for free if you change things again.