You don't need to spend a hundred bucks for a finished bonsai. I suggest you go to your local nursery and buy two or three (not just one) junipers, preferably "greenmound" (Juniperus procumbens 'nana'). Then go to your local library and check out a book on bonsai to read. Style, wire etc your plants while still in their nursery containers and after about a year buy some suitable bonsai pots. One of the most common deaths of bonsai is the result of over watering them. The following will correct this and will work with any contasinerized plant:
Watering indicator

1. Insert a shish-ka-bob skewer or chopstick in the soil to the bottom of pot between trunk and side of pot
2. Remove daily and check for moisture
3. If the stick is glistening wet, reinsert and do not water plant
4. If you are uncertain, place stick against cheek or inside of wrist to feel moisture
5. The soil should be almost dry (just barely moist) before watering

There are many varieties which are user-friendly, (even for beginners!) and most can be found in your local nurseries. There really is no list of plants that can or cannot become bonsai. There are, however, some plants which lend themselves better to bonsai training. Shrubs and trees with small leaves, internodes, and fine branching are easy to work with.

Try checking out a book (or two, or three, or more!) from your local library on bonsai. I find that Herb L. Gustafson's "The Bonsai Workshop" is great in covering all the basics.

-Audric

Dont forget ficus. They are dirt cheap and there pretty hardy (you can forget to water them), you just have to bring them in when it freezes. The Juipers will do fine outside all year long, just protect from wind.
Best bet for the buck, go to Lowes or Home Depot and get a few shrubs that have a decent thickness to the stock/trunk and buy a few of those. Get a few different kinds. Most likly they will be fit for your zone and if you kill one or two, your only out $10. Another thing I look for when I go to Home Depot, look to see if the pot your going to buy has more than one plant in it. I picked up 6 ficus in one pot for $3 the other day. I had to dig for that one, the other pots had 3-4 plants. Once you decide you like this hobby, then dive in and buy a few $10-$50 dollar plants.
As for the tools, alot of books tell you need 10 differnt tools and 3 pairs of shears for differnt parts of the tree. Well, I get buy great with a set of wire cutters and pruning shears from Lowes, a nice Japanese Sisors and Japanese knob cutter from my local nursery and two sets of chopsticks. Then when you decide that you realy, realy love this hobby, then go nuts...
Get the Lowes(or where ever) tools and chopsticks first. You wont need the expensive Japanese tools for a few months. Youll have to transplant your trees and wait to make sure they root good before pruning. If yo need to cut the roots, use the cheap Lowes pruner. So this way the cost is spread out over a few paychecks.
Thats my 2c to the newbee.

I would avoid getting plants with multiple plants in the pot, simply because you will have to untangle the roots, which could result in some plants having lots and others having none (or all of them having little). Also, plants crowded into a container are usually done so to have the most amount of foliage in the least amount of time. Trunk development (if there is any) is usually quite poor and the lower branching can also be a nightmare. Don't start off with a handicap, but that doesn't mean buy the most expensive plants. Just make sure they're healthy and ready to go!

-Audric