The parts aren't all that expensive but the time it takes to solder every joint, heat shrink or braided shield every harness and pin and to offer replacement for even abuse is the difference. Homemade improperly crimped harnesses will short under excessive load or pull out of the connector. I've written up plenty and offered documentation to anyone who wants to build their own.
The thing is that some people can't or don't want to do it. If you want support with wiring or prints I give that too. These aren't assembly built. I hand build, test and stand behind every one. It's not just putting them together. Anyone can crimp with a pair of plyers or use the wrong terminal for different gauge wires. I put the proper pieces together at the same price as buying them at wholesale pricing from gm ($40-$50 based on other forum members) and my wire far exceeds theirs in friction resistance and better conduction. Buying wholesale from terminal suppliers is def cheaper if you have the proper crimper, solder and skill set.
If you are an average joe with some projects, buying a $30 crimper and soldering iron isn't practical. If you are capable, then build your own and save. If you want to have support and warranty, I'm happy to assist. I value my time and think it's fair.
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