FYI:
The price of Gallium is at the moment at 208 USD/kg (99,99% purity).
In the year 2000 it was at about 2700 USD/kg. (not a good investment then, but possibly now?)
Interesting also: Gemanium, often discussed as alternative to SI, is about 2200 USD/kg!
A chart can be seen here: http://www.technologiemetalle.org/kurse.php