Anybody know where I can find cheap figures?

Been wanting to get some. Been a fan ever since I was a kid, and used to have plenty of them like Omega and Energon Skorps but lost them in the storage shed. I'm mainly looking for the ones with the energon keys, and Shockwave/Barricade.

PS. Who is the transformer that is a tank samurai? I used to have him but can't remember who he is.