> cheap, slow boards from China
I've bought about a dozen chinese prototype PCBs for $0.20 a board and experienced 6 days from order to arrival at my door (using $19 shipping). These are tested boards with 6 mil features up to 100x100 mm. And I've done the board designs using their free online editor. This has been mind-blowing.
Check out easyeda.com. (I'm not connected to the company, yada, yada, yada).
As an engineer, my options for prototyping boards are quite expansive because I have money to spend and computer tools at my disposal. These choices range from old-school etching of PCBs; new-school CNC engraving of PCBs; cheap, slow boards from China; to expensive ($1000), fast boards from the US.
Doing this on paper with copper tape is a cool hack, I just don't see a lot of benefit over other options.