I posted this as a reply to someone else's thread but it wouldn't post so here it goes..............
You should take a look at Sister2Brother's blog at:
She posts about free stuff that she has found on the internet and some of them are about 3D programs that she was able to download for free! There was a free version of Bryce that was offered for download and sometimes there are other good 3d downloads that are available for a free download.
I have Rhino! It's a great 3d object-making program. I have Spatch (which is also a free download) for making simple objects. Here is my 3d website: