Yes, paper supplies are subject to copyright, but also big things and 3 dimensional items CAN BE copyrighted...it's really tough sometimes to figure out what's ok, and what's not. Generic things are ok (apple, tree, etc) but identifiable things that have been created by someone else can and probably do have copyrights. I just found out yesterday that the "Happy Birthday" song is copyrighted! There are things in the public domain that can be used. It's important to research things carefully.
I hope that helps!