Ok, what are you going to be using it for? And why only a single edge? Remember, the more information you give people, the better they can answer your question. I like the Cold steel ones, and I carried a minipal on my keychain for years. Some of the larger ones were nice to. Mantis has the "wicked" which is an interesting one, though I think it has 2 edges. For what you are willing to spend, you should be able to get something decent from a custom maker as well. And then you can get one made to exactly suit your needs.
-Mb