Logo's are important, but I don't know that they're that important for a small business start-up. (In terms of everything else that's needed for a small buisiness start-up) I guess I just don't see spending hundreds of dollars, up front, on a logo when you don't even know if your brand will sell. And this is coming from a guy who spent a couple hundred dollars when he didn't know any better. I worked with an artist, for what will eventually become my hangtag graphic, and it took three goes for him to understand exactly what I wanted. Fortunately for me, the artist I was working with was a good dude.
At the time, I thought that the artwork he was providing would be a good logo. But then after more research I decided to take a piece of the artwork and roll with making my own logo for the brand, inspired by one that exists already.
In the end, I'm happy with it. I like the way it turned out... but I probably could have saved myself a couple hundred dollars if I would have been more patient.
One more note, if you're getting into T-shirts, then its a fair assumption that you must have some sort of love for graphic design. Take your time and you can come up with something yourself. Then spend the money you saved on inventory or equipment...