When I first got into star wars collecting I bought alot of books that would help me price my figures and decide how much money I should spend on them. There are plenty of books to choose from but they can be hard to find. You can find them at your local library or bookstore but many you will have to order. It is good to compare different books to see if the information is accurate. Here is a list you might want to check out.
-Star Wars Vintage Action Figures by John Kellerman
-Warman's Star Wars field guide by Stuart W. Wells the third
-Star Wars 1,000 collectibles Memorabilia and stories from a galaxy far, far away by Stephan J. Sansweet with Anne Neumann
-Star Wars from concept to screen to collectable by Stephan J. Sansweet