This is an old revision of the document!
You can buy a mob spawner at spawn for $150,00 by right clicking on the sign. You can use them by placing them and right clicking them with a spawn egg of a mob that you catched by hitting them with an egg. Just specific mobs are allowed to be used with spawners.
please expand that list if possible
Trying to set a spawner with one of those mobs will result into one mob getting spawned and the spawner destroyed. This is enforced by the NoSpawnerChange plugin.