Just a thought, but do you have a fly shop nearby that might be willing to "sponsor" the class? Maybe they would give you a good discount on those tools and you could promote that shop during the class which would benefit you, the kids, and the fly shop if some of the kids did decide to take up fly tying or even just go there for materials.
Not sure how realistic that is but fly fishers/tiers seem to me to be quite a generous bunch.

Karli-Rae