Yeah Zbrush is the king of digital sculpting software, I absolutely love it. You can start out with Sculptris and then when you make enough money get a copy of Zbrush.
Two solid modelers that you might be interested in looking into are
DesignSpark Mechanical and
Fusion 360. DesignSpark Mechanical is SpaceClaim, which I feel is the best direct solid modeling software package in the world. However, the free version, DesignSpark Mechanical, does not include a 3D mirror command so I always warn people about this when I recommend it. The $4700 SpaceClaim does have the command of course, they just removed it from DSM so as to keep their paying customers happy.
You can still use the software to do whatever you want, but when it comes to something that you would like to mirror to save time, you can't, you have to redraw it in the reversed direction.
I slipped a word in there,
direct solid modeler. Yeah, of the solid modeling packages out there, there are two distinctly different types, feature based and direct. Here's
a video put out by SpaceClaim explaining the two different types.
Fusion 360 says free trial, but it's actually free forever if you're going to use it for personal use. It is also free to use for one year if your going to use it in conjunction with a startup company. By the way, not many people know that most of Autodesk's products are free to use by students for three years. Fusion 360 is also a direct solid modeler like SpaceClaim. No one ( for now ) can make software as easy to use as SpaceClaim because they have patents covering numerous aspects for the way it works, but Fusion 360 is very close in a lot of ways. Fusion 360 is similar to Photoshop CC as it is also cloud based.
Try them out and see how you like them.