The Mothersite of my creations is Daz3D, 3 of the main programs I use come from here. Bryce 5.5 is a free download, or use to be. Daz Studio 3 is also a free download, but not a stand alone program. Enjoy.
http://www.daz3d.com/

TrueSpace 7.61 is currently a free download, better get it now or you will be sorry. Great program.
 http://www.caligari.com/downloads.html

If no luck with free bryce on Daz3D try Cnet.com A trusted site.
http://download.cnet.com/Bryce/3000-6677_4-10696717.html

Most Digital Creations is by far the best site to go to for free stuff, aswell as cheap priced items to.
http://www.most-digital-creations.com/freestuff.htm
 
The second best is EvilInnocence, also tons of free and affordable items.
http://www.evilinnocence.com/

Another great site is Rederosity. free items and help.
http://www.renderosity.com/