Inspiration can come from many directions. The internet, magazines, catalogs, and books can be helpful.
When you do find something you would like to make, it is important to know whether you are allowed to use it. Pictures of famous people, sports and team logos, photos that are not your own, even your school logo/mascot should not be used without permission. Generally, it is best to stay clear of copyrighted/trademarked images. Create something that is your own.