A type coin is typically meant to describe older us coins. People cant typically afford a whole set so they just buy one of each type of us coin minted. They also make TYPE COIN albums. http://www.ebay.com/itm/Dansco-7070-United-States-Type-Set-Album-/141346294505?pt=LH_DefaultDomain_0&hash=item20e8e54ae9 People also put these books together because they can typically buy one really nice coin from each type and use this kind of book to display and show friends. Type books are awesome to share with friends and relatives to show them the history of us coins. Hope that helps you understand the idea. JW