Demand drives price up. That's why immediately after the update you could sell sanjaku tengui for 10k/stack or more. Then, when people see you can sell things for a good profit, they make them. Then this supply drives the price down. If you see 80 stacks of shinobi tabi up on the AH, make something else. If you see 3 stacks, then make the shinobi tabi and sell it for 6k.