Headphone Dilemma

I'm getting ready to introduce the iTouches to the kids. The only thing holding me back now is having enough head phones for the kids to wear. Here are my thoughts on having individual sets or class sets:

Expense:

The cheapest I can find headphones are 4.99 a pair. We can't use the ear buds because they are too large to fit into the firstie's ears. I would have to purchase 18 pairs. The kids could all use the same ones, as I've done for the Shuffles. Then I would only need 4 additional pairs.

Asking so much already:

I've already asked for class money to help pay for class parties, but then the small amount I got I used towards ball chairs (that I can no longer use). Should I ask for parents to pitch in for a pair if they don't want their kid to share with others, and then pick up the tab for those who don't? Gotta keep it equitable.

Parent Choice?:

Do I let the parents send in their own, or have a set price and purchase them so they are all the same?

Licing on the Cake:
Um, would you want to share headphones with the Class Lice? I think I would pass.

Just thinking out loud. Would love to hear ideas and suggestions.

Thinking ahead to the short week...I hope it is free of parasites and dog poo. I don't think I can take on much more. I can't imagine what could be next....well, I could, but I won't in case there is some suggestive power of thought.