Well Whiting's 100's should tie about 100 flies, hence the name. In my experience, most of the stuff you buy for tying will tie a lot of flies. So a pack of peacock hurl, hair's mask, or a couple pheasant tail feathers will cover many flies, but I don't know how many exactly. Same for wooly bugger materials, which is a great place to start. Might not be bad to wait for the hackled dry flies until you get the wooly bugger and some nymph patterns down.
As it turns out, a nymph tie along
just started with the pheasant tail nymph. It might be tough to start with smaller nymphs, but if you tie them on size 12 hooks it could be a chance to see step-by-steps and get feedback on your tying. I linked it to the page containing the first pattern, earlier pages might have some good info too.
As for materials, local shops are great, but online has tons of resources. JS
Stockard, Casters Fly Shop (free shipping), Fly Tyers Dungeon are three places I get materials from.