The 1847usa section of Stamp Smarter will help you identify and learn about US stamps. Much of this content was originally developed by Bob Allen; we owe a great deal of gratitude for his original efforts and allowing it to stay published.
Note: Many updates, corrections, and enhancements have been made over the original 1847usa site.
Although 1847usa is an identification site and does not provide stamp values, you are probably wondering how much your stamp is worth. The first stop for most collectors is to look up the value in a Catalog. Bear in mind that the values provided are prices dealers ask for nicely centered sound stamps. Stamps with small flaws or less than ideal centering will sell for much less. Recent editions have added a supplement that provides values by grade. The PSE PRICE GUIDE is an online guide that provides values by condition and centering. The POWER SEARCH at Robert A. Siegel Auction Galleries is an excellent tool for identification and auction realizations. The PHILATELIC FOUNDATION, which issues the PFC certificate, is generously sharing its certificate archive with the philatelic community.