It cost $8 which is about half of a regular bubble counter. Just an Ehrlemeyer 500ml glass flask, rubber stopper, and 3/16" rigid airline. I filled it with 100% vegetable glycerin and a little bit of yellow food color. Underneath is a blue moonlight, courtesy of Sherman.
Ooops. Forgot about the mount. That was about $10...typical DIY right? Always over budget!