Coreswap breaks down like this:

 

I have stock headlights.  I build these, which means they're called custom headlights

You have stock headlights. You end up shipping those to me so I can use them for the next guys custom build.  We call those Cores.  The Cores are just the stock lights that I trade with you, or "swap" with you.  

 

The two key features of the CoreSwap:

 

1st, you are being charged for the convenience of the service.  I could say the only way to get the lights done custom is to send in your stocks. That's fine, and super easy, and simple to understand... but almost nobody can do it.  When you can, it saves you time and money.  When you can't there needs to be a solution, which isn't simple, costs money up front (for me), and it makes the process easiest for the buyer because they dont have to ever be without headlights.  So its an option you pay for.  

 

2nd By me building lights that I own, with your money to paint, add parts, etc. and then shipping them to you, I take a big risk that you'll never send me your stock lights back.  Not because I dont trust anyone, but because I'm still at this very moment out 2 headlight sets that the customers for whatever reason decided to rip me off and not send back.  That sucks.  Neither of these two people paid a holding fee of 150 bucks that I now have to do as part of the CoreSwap.  I charge 150 bucks up front, then hold that money until I get new lights back.  If the lights are all damaged and broken, or unusable and somebody figured they could swap their bad headlights for new hooked up headlights, then the 150 would not be refunded, and I could use it to buy a replacement set of "cores".  This has never happened to anyone who paid the 150 holding fee.  I always get the lights back, and then release the funds back to the buyer.  They want their money back, and I want my cores back.  It just works... but it sucks that to use the Core Swap service, you need to pay 250 bucks up front, on TOP of all the crazy charges for the build itself.