Any time I visit a fly shop, I pick something new up, even if I don't think I'll need it right away. You never know when that little 2.00 thing will come in handy. For example, anytime I see a new color dubbing that I think I can work with, I'll pick it up. Something that catch's my eye. There are basic things, then there are things that you see and say, "Wow, that looks great", like a good neck.
Is fly tying cheaper than purchasing? In the short run, no way, but in the long run, you better believe it. Fly's cost on average, $24.00 per dozen. After you purchase your equipment for a few hundred bux, the rest (other than necks) is pretty cheap. Dubbing is about $1.50 per bag. Microfibets are about $2.50 for a bag, CDC is about $4.50 per bag... This all depends on where you purchase these things from. Elk hair is about $4.50 for a little patch (about 50+flys)...
One thing I learned about hackle, is that if it's not good stuff, your fly's will look like shit. Yeah, they will probably work, but when I tye flys, if they don't come out looking like I picked them up in an Orvis catalog, I get out the Razor blade and start over until they look the way I want them to look.
One more thing. If I'm on the river and a fly has just about had it, I save the hook and recycle it! Hooks are $4.50 for 50. That is of course if you're purchasing the Tiemco hooks. I really should start purchasing these things in bulk!
That's it for now.
For that $12.00, you can make yourself a quite a few fly's.