Here's an easy DIY costume: Luna Lovegood from HARRY POTTER!
Start with a white or ivory button up shirt and a plaid or wool pleated skirt.
To bring the look home, all you need to buy is a Ravenclaw tie and a wand!
Add funky tights. Luna rocks radish earrings, so there's no such thing as "too far!" Let the magic begin. Lumos!