Great post Twospots.
For dries, I'm a big fan of Sparkleduns and X Caddis. They use the same inexpensive materials (fine deer hair sold as "coastal' or "comparadun" deer hair instead of expensive dry fly hackle) and are tied basically the same way. Comparaduns are similar to Sparkle Duns, but have split tails of microfibbets that are often more difficult to tie for beginners.
They can be tied in a variety of sizes and colors to imitate specific hatches of mayflies and caddis, and are good searching patterns, especially in slow to medium fast water. Because they have a "shuck" for a tail, they do a pretty good job of imitating both the emerger and dun stages of the mayfly and since they sit low in the water they also do a pretty good job of imitating the spinner stage as well. The caddis version is also very effective, and both can be twitched under to fish wet.
Hook: Standard Dry fly hook
Thread: any color (match the general shade of the fly or body color) 6/0 (or 8/0 for smaller flies)
Wing: Small clump of fine deer hair. On small flies 20 and smaller use CDC instead. For mayflies (Sparkle Duns), tie the wing with the tips facing forward, for the X Caddis, tie the wings in with the tips facing to the rear.
Tail: a "shuck" of Antron or Z-lon usually light brown/amber
Body: Dry Fly Dubbing (Fly Rite, Superfine etc) in whatever body color
They can be a bit tricky to tie at first, but once you've tied a few you can crank them out. You can find detailed step by steps here for the Sparkle Dun (along with some easy to tie patterns) here:
Craig Mathews' Sparkle Dun
and here for the X Caddis:
Fly Tying Patterns for begginers - Copperfly.net - The X-caddis Flishing Fly
dry fly hooks in assorted sizes 10-20, (especially 14-18 for trout to start)
Antron, Z-lon or Sparkle Yarn for tails in amber or medium brown 3 bucks
12 color dry fly dubbing assortment 13-17 bucks
Wings- a couple patches of coastal deer hair in bleached, light gray, medium gray and dark gray. A 2" x 2" patch will cost about 3 bucks and is enough to tie about 100 flies. Add some CDC in white and medium gray if you want to tie some small ones size 20 and under (easier to work with than deer hair on small patterns, just tie it the same way using CDC.
You can google up a hatch chart for your area to get a general idea of sizes and colors of naturals to match hatches and use the sizes and color scheme of other "standard" patterns-- olive body/ medium gray wings for a Blue Wing Olive, tan body/ gray wings for March Brown, yellow/orange body light gray wings for Sulphurs, cream body/ bleached wings for Light Cahills etc. or tie up a bunch in a range of sizes with dark bodies/dark wings, light bodies/light wings and you'll come pretty close to whatever you might run into on the stream.
The drawback of these flies is that they donít do as well as some other patterns in fast water (harder to see).
If you fish a lot of fast water, some easy to tie patterns that use inexpensive materials are the Haystack (forerunner of the Comparadun and Sparkle Dun, also using deer hair wings) and The Usual (using Snow Shoe Hare feet for wings and tail for flotation). These were invented by Fran Betters to fish the Ausable in NY, a fast freestone stream. These can also be tied in a range of shades, and you could use them in the same places youíd use a Wulff or Humpy. These flies float like corks, and are easy to see as they bounce around. Because fish don't tend to be as selective in fast water, you can often get away with larger sizes, and just some light ones and dark ones would be good for your box. You should be able to see one or the other against the water.
Haystack step by step
The Haystack: One of our Favorite Smoky Mountain Trout Flies | R and R Fly Fishing
Usual step by step
"The Usual - Fly Angler's OnLine Volumn 10 week 46