If you're at all handy with a hairbrush, a few dollars worth of gel and spray glitter will replicate most of the styles. Pick up a cute scrunchie or clip ahead of time to add in. You could even add in some streaks of spray color if you'd like.
Most of this can be found at dollar stores, Target's Dollar Spot, and girl's jewelry stores like Claire's.
You can also pick up some inexpensive makeup or use a bit of yours to give them glittery eyeshadow and lip gloss.
The trick is to do things that are completely over the top and not usable in every day life--the biggest hair you can make, the frilliest scrunchie you can find, the brightest purple hair spray, etc. That will make it seem special and not just an everyday ponytail.