Those are not actual lego sets. They are pieces broken out of lego sets that are no longer sold. It's marketed by a third party seller to the collector's market. Each figure came from larger sets. I'm sure you are aware of this, yes? And if so, you agree that your post is very misleading, yes?
http://www.amazon.com/2013-Lego-Ninjago-Kimono-Ninjas/dp/B00...
Any of the LEGO Ninjago stuff is ridiculously expensive.
This one is $20 for a 2" figure:
http://www.amazon.com/LEGO-Ninjago-Minifigure-Titanium-weapo...