Yes big difference in price. Big difference in what's in the kit too. I always go with American AutoWire because I always need all the extras they include. Many good parts other than wire. Very complete. Just read the list.
Price:
High end kits use cross linked GXL insulation and lower end use PVC insulation. PVC is adequate and GXL is better. (may work better with automotive connector crimps and connectors and has a higher temp rating). It's also about the number of circuits, the fuse panel, the amount/quality of extras, completeness, and the instructions.
If you are only going to do one truck and keep it for life, consider the high end. If flipping, different story. They less expensive will wire a basic truck. Not too many circuits in our trucks.
