The perl lib is very basic. It's mostly there to help you set up communications with the server. Most of the heavy lifting is done via xml.

Yes, it's not free in either sense, and it's in Java, however the quality of the charts are very high (flash, png, ...), and the customizability (a big one for us) is extensive.

The company I work at is all perl/mysql/apache. This is the only major commercial tool we use and it has been worth it.