We measured their waists, and cut some elastic to fit. Then I made a casing in the fabric for the elastic. Once we had the elastic threaded through, I used the rolling cutter to cut the fabric into strips. Voila, grass skirts on the cheap! We used fabric I had laying around, so besides money for the elastic (and at 59cents/yard it was a score), these were virtually free. The Princesses loved wearing them, and had a blast at the luau.
Their favorite part was the pinata. Someone else was taking pics of the whole party, and I know he got some of the girls. I just need to see if I can get those from him now. I'm positive there's a really good one of Princess C whacking the pinata, and one of Princess R with her bag of gathered candy.