Everything Mark said is right on.

One other thing to think about is what you plan to do.  If all you're going to be interested in is outdoor landscapes, Carrara can do it but there are other packages that can do it better.

Carrara can be a good modeler but it isn't a great modeler.

To emphasize Mark again, Carrara is a one package do it all for the hobbyist and it can bang out some really great stuff in the hands of an experienced user and artist.

if you want to do certain types of things, there might be better choices.

Let us know what you're into and maybe we can help.

-Kix