I want to second (third?) the idea of using temporary tattoos. I had read about it and decided to try it for our next trip. I got some Little Mermaid tattoos at the party store the other day and tried it on an old band from our last trip. It worked so well and looked so good that I'm going to go ahead and keep that one to use next time.
I did also order some of the character magic bands from the Disney Parks Merchandise App (and you can get some of them--though I noticed not all--through disneystore.com), too. They're more expensive, but I was able to get one with a Stormtrooper, Olaf, and Chip & Dale for my kids.