Oh jeez, costume drops. You just reminded me of a hilarious bit.
When inventions got released for City of Heroes, there were recipes to make costume pieces. Things like wings, rocket boots, etc. But Cryptic/Paragon made the drop rate like... one tenth what it should have been. Oops.
The result was a textbook example of supply and demand. Rocket boots in particular were VERY popular, but they didn't drop much if at all. Result? The rocket boots recipe on the marketplace was even more expensive than a maximum level unique set enhancement recipe.
This was fixed eventually, but I still found it amusing.