Reddit mentions of Bonsaiboy Heavy Duty Bonsai Wire Cutters.

There are lots of options, so it's tough to make recommendations beyond price points to look at.

I've found that decent shears tend to start around $30-35, and good concave cutters are rarely under $50. The home depot wire cutters will obviously cut wire, but the nice japanese ones let you get right up to the bark without making a mark on the tree, which is really important when you are removing the wire later. Here's an example of what I mean:
http://www.amazon.com/Bonsai-Boys-Heavy-Duty-Cutters/dp/B002C6BOQY/ref=sr_1_5?s=hi&ie=UTF8&qid=1368845322&sr=1-5&keywords=bonsai+wire+cutter

This is probably about the cheapest I would personally go for this type of wire cutters, but you may be able to get something similar for less.

The important thing is to get the nicest tools you can afford without blowing your budget on any one item. For $100, you should be able to get a pretty decent set that will last you a while. The first couple years I did bonsai I only had a $15 pair of shears and a cheap radio shack wire cutter, so you're already way ahead of the game. ;-)

Or you could just get the $48 ThinkBamboo set and get one of everything - I'd just want to hear from someone else who has it first. It just seems way too cheap for that many tools.

I personally tend to slightly overspend on tools, because I've learned that the money you save sometimes gets paid back in frustration from using crappy tools.

EDIT: Don't forget to save some money for trees!