New should mean brand new,mint,unused,Zero damage,as if it were literally just purchased at a store and "fresh" out the box. Used is waaay more complicated for obvious reasons. There is a precise gauging system especially with books and collectibles that ALL sellers should follow or risk a return and poor review. Used items,in my opinion should be communicated in great detail at your request,prior to purchase.
Collectible can be an OOP (out of print) item and more rare,very hard to find in new condition. Everyone wants it and the price has skyrocketed. Also,the world of serious collectors and their quirks actually dictates any market values for the more cherished or unique items.