You can make your own PCBs quite easily with cheap chemicals, a laser printer, and some tubs to agitate the mixture. It's a bad idea though, when you can design them and get them made online incredibly cheaply.
There are some home-brewable ways for single layer boards, particularly one sided -- you can do the old school copper board + mask + etch with something like ferric chloride. It's pretty easy but you do want to be careful as the chemicals are a bit nasty. Newer school is to print the mask and transfer using a laminator.
You can also physically etch with a milling machine. It's a bit more expensive but low startup cost if you already have a small cnc mill. You probably have access to one at a maker space. That's most likely the easiest way to go.
It is incredibly easy to use an on-line service to specify and fabricate PCBs.
I just did it for an adapted multi-sensor temperature system and the boards were about $5 and tooling costs were minimal. The quality far exceeded anything that I have ever been able to do by myself.
Self-etching is a royal pain for a medieval quality result. It probably winds up costing more than ordering the boards from PCBWay or similar manufacturer.
It's basically impossible to made a modern PCB at home; you can certainly make something that's not even at the quality level of an early 1970s PCB: single-layer, single-sided, no solder mask, but that's about it. For modern circuitry, you want at a minimum double-sided, plated thru-holes, immersion tinned, and a solder mask. For more complex circuits or those needing better power/ground shielding to keep noise down, you need 4 layers, which is totally impossible at home.
I guess I wouldn't say common - but hackerspaces and especially fablabs will often have a Roland CNC machine capable of carving PCBs out of copper-coated-fiberglass - but once you go through all that (paying for a couple broken 1/64" routing bits as you learn to use the machine...) it starts to make sense to pay $5 per square inch at oshpark
Whenever I see that, it means having to pay somebody quite a bit instead of do it yourself.