There are all kinds of souvenirs that you can get for your friends! Just try to think about what they each like, and how much you what to spend on each of them. If you can come up with answers to those questions, you should be able to find something that they will like.
Some suggestions: T-shirts, jewelry (if your friends wear those link charm bracelets, you can get links with Disney characters on them), and Disney pins (if they collect them). My favorite souvenir from WDW is a crystal that I got on my last trip. It has Tinker Bell in it, and it is so pretty. If your friends like Disney characters, and you're willing to spend about $20-30 on them, you can get these crystals at the shop inside Journey Into Imagination in Epcot.
You may also want to check out the shops in Downtown Disney (especially the World of Disney shop) for other cool ideas.