My DH's answer - a haircut at the MK barbershop! It usually runs around $18 with tip.
Since you said it was for your DD, I would suggest a pair of Mickey head Icon birthstone earrings. I bought a pair for my DD at the WL gift shop - they had all birthstones. (providing she has pierced ears). You didn't say how old your DD was, but what about some cute hair accessories (hair ties, barrettes, clips etc). They even had cute princess luggage tags.
My DD is 5 and loves the back scratcher she purchased on our last trip.
Hope this helps a little.
Colette