You can find a variety in most gift shops, however the biggest concentration will be at DTD in the World of Disney and the memories store (sorry can't remember the name, all scrapbook and photo stuff). You will find many different punches for example and the selection is hit and miss in the parks, but I found that WOD had them all. However, I was disappointed as I had hoped to find more unique stuff at the scrapbook store. The paper packs were interesting, but there were too many pages I would never use - just not my style. There are dated borders and stickers for the theme of the year that you won't find elsewhere and might be something to look for. IMHO, I wouldn't make a special trip to DTD next trip for scrapping stuff.
My suggestion would be to scout out all local sources of supplies so you have an idea of what you can get at home. For me, that was the only thing I bothered with, as online shipping to Canada with fees and customs isn't an option. However, you might want to check out Paper Wishes as they and many other online places have lots of variety. As another poster said, check out the scrapping threads, there's LOTS of info there. Once you've done a bit of legwork, keep your eyes open everywhere in WDW and buy what isn't available at home. The licensing seems to have been expanded, so (in Canada anyways) there is more available in the stores now.