Limited unique item

Whats a LimitedU?
A LimitedU is a hat, gear, or face that only had a certain amount of the item in stock, and once the item was sold out, it could be sold for profit by Builder's Club Members. LimitedUs are Rare and should be sold under what they were originally sold. It is unknow if someone deletes the LimitedU that it will be lost forever making the item rarer, but it would make its price go up even further.