I use an IBM model M keyboard.  I bought a few of them years ago, for $5
each.  They are excellent keyboards and built like a tank. There is a
company in the U.S. making new ones and they even have a Linux version,
with a Tux key.


Not $5 but not bad.

There are no specific Linux keyboards, but they do sell Linux keycaps that can replace the Windows keys for those who want it.
- Evan