Comment by waerhert

Indeed the cost is mainly from assembly. The board itself is 2 layers, all default settings at Jlcpcb except for the color which is now black as opposed to the default green. This increases the cost of the board a bit. You can experiment with their calculator to find out more. I've ordered 5x each version, which is also the minimal order amount. I did try to stick to the standard library as much as possible but it's not easy once you go beyond standard passive components. Can't currently tell the exact difference it would made if I had soldered the THT by myself, likely not enough for me to bother. You could be right on that last part. The details on it are not as fresh in my head anymore. It is definitely true that you want to minimize the amount of different components. If you need 4k and 6k resistors you're better off buying 2x2k and 3x2k instead.