StampManage USA Scott Catalog Stamp Collecting Software Save hours of data entry by picking from thousands of complete variety listings of stamps from the USA &amp; US Possessions Comprehensive and up-to-date Market Valuations in several grades, including Plate Block and Mint Sheet valuations where applicable. Use our amazing eBayT search feature to quickly search current (and completed) auctions by SCOTTT number Liberty Street Software is officially licensed to use the SCOTT stamp numbering system Catalog your Mint and Used single stamps, Plate Blocks, First Day Covers, PNC Strips and more. A great way to find the recent selling price of stamps you wish to sell or buy.