Just about anything in the player's handbook is available except exotic materials like mithril or adamantite. And nothing excessive like a galley or barge or waterclock. It is assumed that you probably already have these and they are owned by the family. And of course nothing silly like 50 everburning torches. I'll have final say so of course.

Even masterwork tiems are available. Since you are all part of a wealthy family i expect everyone to have masterwork armor and weapons.