Hi Daniel,
As you may have noticed, most of the forum is written in a language other than English. It is German because this forum is based in Germany. I guess nobody will know how much the cheapest L. williamsi pair on a fair in Los Angeles, USA, will cost. In Germany they became pretty expensive because they are protected by CITES now and there aren't any legal exports anymore. A pair costs about a 150 EUR at least.
No, a terrarium or should I call it a tank because fish tanks are what you normally use in the USA, with a size of 8" x 8" x 8" or 8" x 8" x 12" is way too small for a Lygodactylus pair. A proper European style terrarium with a size of at least 1.5 feet x 1.5 feet x 2 feet would be a proper enclosure to keep them. Maybe an Exo Terrarium tank will do with proper lamps.
You should not even try to handle these small geckos because you won't be able to do this unless you force them. It might kill them. Be patient and observe them. That's it.
If you are seriosly interested in these geckos, start reading here:
http://www.dwarfgeckos.com/lygodactylus/l_w/lygodactylus_williamsi.phpKind regards,
Robert