Because the pedals are just for my own use, I have no problem fixing things if they break later on. For that reason, I am happy to use cheaper components. For example instead of Pure Tone or Switchcraft sockets, I buy bulk packs like this. And this 600 piece resistor set is about the same price as 8 resistors from Jaycar (don't worry, Jaycar still get a lot of value from me )

I haven't kept detailed expenses though, so my prices might be a little off, but not by much I think.

To some extent, you don't need much electronics knowledge to build a PCB kit or stripboard build. It's largely solder by numbers. However it does help a lot when things don't work, or when knowing if substituting one part for another will be OK (I often do this to avoid more parts orders).