Some items can only be bought by people with Builders Club. However, unlike premium places, TBC and OBC have their own exclusive items as well. The more premium memberships can still buy lesser membership items. For example, you can buy a BC Only item while you are currently subscribed with OBC. Many bodies are for BC only, for some certain ones, NBC can have them to. While this is usually by hacking, many people agree it would be better if it was for all.