I use the Star Wars Collecting Database. It's put together by Todd Carlton who has published several collecting books... the "Super Collector's Wishbook" series.
You can download the program to your computer for free and try it out. The database is massive with information, pictures, variations. Easy to navigate once you get used to it. If you pay for it, you can keep up with your collection, information and even print out reports. The bulk of the work is already done for you. All you have to do is go in, click what you have, add to "your collection", enter what you payed for it and your done. It's also backed up on the internet in case you lose the data on your computer. People from all over the world have and do contribute to it constantly. It's updated once or twice a month with new items and some price adjustments.
Here's a screen cap of the interface. There's also a phone app.... absolutely great when out in the field and you need a price look up or quick info.
You can get the data base here...http://starwarsguide.net/filemgmt/index.php
Always looking for Vintage Star Wars Holiday Special Items