I was 10 when I got my first good PC, good because before it, what I had was called 486. New PC was Celeron, far slower than present standards, but that was the beginning of my 'computer freak' nature. But the point here is not about my love of computer but the result of this nature. I got my PC filled with 3-D Max, and I knew nothing about it, nothing and neither was in high interest zone. I soon realized and removed it from my PC(I am bad in drawing, worst in my family).
Now is the time to go 3-D, you can if your time permits can work on few freely available 3-D softwares.
Blender
DAZ Studio
Blender
First on is Blender(My personal favorite). Its under GNU general public license and is based on Python. Now what open source allows is well known is web community, it provides some regular updates, so we can say that it keeps on changing. Its really powerful. It have a very long list of features. More than that its library is also increasing and one thing which matters to me most is that IT IS NOT BIG. Yes it can not perform in the same way in which MAYA perform, but who needs Maya or for that matter 3ds max for regular office 3-D work.
Maya is like best best brush to paint, but I dont need best brush to paint my 1st grade drawing sheet. And let me tell you Blender is no 1st grade drawing brush.
DAZ Studio
This came to light much recently when it was covered on Download Squad by Ryan Carter.
Telling you all frankly I am not eligible to suggest any thing about DAZ Studio, as I haven't downloaded it yet.

This is one art sample which is using DAZ Studio and is from their site.
This is what they have got to say
DAZ|Studio is a free software application that allows you to easily create beautiful digital art. You can use this software to load in people, animals, vehicles, buildings, props, and accessories to create digital scenes.
But I dont think that it is open source as it not mentioned any where on their site.
And yes its a tell-ware.
Thinking whats a tell-ware?
They simply want you to tell your friends about it, at least 2.
Why?
DAZ Productions has a made a committment to keep the DAZ|Studio core application free to the public for as long as possible. In order for this to be possible, DAZ relies on the revenues generated by the purchase of content available in the DAZ online store. The more people that purchase regularly from DAZ, the more development that can be subsidized and the longer the DAZ|Studio core will remain free.
If you want to know that what am I going to do, then let me tell you that I have already told 2 person and you are third. So I have already done my good.
My suggestion is that you should download both, try them, test them as per as your needs, and then uninstall them as I did when I first got 3ds max on my celeron.