Material Choice determines how hard tying will be!
Dry flys. If you are like I was, I didn't like tying dry flys basically because of the hackling. I also was using Metz dry fly necks that had thick hackle stems and short hackles. When I switched to Whiting dry fly saddles it simplified dry flys so much I was shocked. Whiting bronze grade dry fly saddles are around $20.00 and well worth it. Supposedly there are enough feathers to tie over 500 flies.
Smaller threads work for larger hooks, but larger threads don't always work for smaller hooks.
When I first started tying I was under the impression that I needed to get every diameter and color thread. WRONG! If you have a delicate hand, you can buy thread called spiderweb which is very delicate and only comes in one color. On the other hand you can also buy very strong 17/0 uni-thread (above) which is clear, thus eliminating the need for every color thread under the rainbow. Don't get me wrong, if your tying salt-water or need extra bulk on your fly then get the appropriate thread. With all threads, do yourself a favor and get a ceramic tipped bobbin.
A Note on hooks...
A couple initial concerns with a hook is how strong it is and how sharp it is. Lefty Kreh states that one of the overlooked errors of fisherman is the sharpness of their hookpoint. Two ways around this. One is to manually sharpen them, or the other is to buy high end tying hooks, i.e. tiemco, mustad signature, partridge, daiichi, orvis. The difference here is that you can buy a mustad standard dry fly 94840 with 100 hooks for around $8.00 or buy 25 mustad signature dry fly r30 for about $4.00. It's up to you really. General rule is if you're fishing 18 and smaller you may consider buying the more expensive hooks.
Where to buy...
I don't receive anything for referring people to any business. If you're looking to buy online here are some links as follows.
Mad River Outfitters (free shipping over $25) (currently not recommending this because of shipping time i.e. order placed 9/18, order still not received 10/07.
J. Stockard (pay's for your reviews)
I personally would prefer to support my local shop, but for the budget minded tyer some shops are too concerned with pressure selling guide trips and high ticket items. Last time I went local looking for a standard streamer hook (which they were out of), I instead was held up for an hour and told how I should buy a tibor custom reel for my dad for father's day. Experiences like that encourage online shopping.