I would recommend skipping all the lesser used beginner's tools and get a package like Rhinoceros. As said above, it's not that hard to learn and you can make almost anything with it. Then later you can get the free Grasshopper plugin and gradually become a Rhino expert. I would go for a package that some professional companies use as well, and invest some time studying it, so then you may have a head start if you ever want to get a job in art/design.
If you just want to have some fun, you may want to try out the free sculpting program Sculptris. It's awesome and incredibly easy, you hardly need any instruction and can just start playing around with it. I've used it for some professional sculpting work for 3d printable items as well. Then you can get a free STL editor like Meshlab and Netfabb to hollow out and fix up your piece and convert it to a printable STL.
Have fun modeling!