I was working on a portable radio configuration and wanted a smaller key that was essentially disposable. Print the model, add a hacksaw blade and a few screws and you have a serviceable keyer, Is it the greatest keyer in the world - no. But for about $1 in parts and a bit of 3D printing it works.

Printrbot

Simple Black

Doesn't Matter

No

3

20%

I got a working model the first time, so I didn't do much refinement. If I were to do some additional work, I'd hide the cable rather than use a zip tie. There are some other designs on thingverse for those that prefer a squeeze paddle.