Precision. $30 meters tend to not have it.

I paid ~$400 for a 6.5 digit meter recently, and it's been worth every penny. Not everyone needs that precision, though, and that's fine. :)

Anyways, if you want a meter in that price range, at least get one with standard detachable probes. That's generally a sign of higher quality. This Extech meter is an excellent choice, for instance.