See also: T13689: A Considered Review: 3D Printing

Expectation: PCB manufacture is a specialized industrial process that is far out of reach for individuals. Designing PCBs is difficult. PCB manufacture is impractical at small scales. Lead times are long and minimum order sizes are thousands of units. Better to give up this dream and practice making solder bridges on perfboard. Tip: keep a little cup of legs you've clipped off through-hole components on your desk to help make solder bridges!

Reality: This is completely true, perfboard is your best --- Oops! There's actually a Magic PCB Faucet somewhere in Shenzhen and it costs $5 to get a stack of PCBs flown across the ocean in a couple days. They're also really easy to design.

Here's a PCB for a USB power switch (commercially available for $6 on Amazon), except that it's an opposite-switch and has a light that goes on when the power is off: