Cartoon character costumes are now more widely available than ever before and these days, they are not just for children!
Professional Costume Suppliers
One place to try is allfancydress.com, where you can buy costumes based on characters from The Simpsons, Star Wars, Marvel Comics Superheroes (such as Spiderman) and the various Disney animated features. Escapade.com has a similar range, and covers more adult animated comedies, such as Family Guy, and also stocks costumes for pets! Wildnightsfancydress.co.uk provides for adults and children and as well as The Simpsons and Disney, also caters for fans of Scooby Doo, South Park, The Muppets and Teenage Mutant Ninja Turtles. Of course, if your own little prince or princess wants to be a Disney prince or princess, Disney Stores themselves produce a large range of costumes and includes characters from other film franchises (e.g Star Wars, Iron Man). Larger high street stores also stock cartoon character costumes, mostly for children - Argos and Woolworths are good places to start.
Do It Yourself!
A cheaper and more fun option is to put together a costume yourself or with friends. Cosplay, as it is known, is all the rage, and covers every cartoon TV show and film you can think of, and is especially popular with young women. If you're a beginner, you might find it easier to base your costume on a 'human' character, such as Fred Flintstone or Penelope Pitstop, than on based on a superhero or an animal character. Facebook is a great place to get ideas - look up the 'Geek Girls' page for instance. Or you can watch this video which shows you how to get started: