Blender is surely best option, in the free field.
Anyway, Anim8or is easier. But less powerful, and maybe it's 3ds export is only good for the collissions, but not camera or lights export. But I am not sure.
www.anim8or.com Strata was easy and good and there was a free version years ago.
you have some others ones...let me think...Truespace 3.2 is free... available at download.com, I thing, find through caligari's site, but Anim8or and Blender rendering is much better...
you have also Art of Illussion, but need java JRE installed, and ..imho Anim8or is easier, and I prefer personally Blender better....Though AOI has a magnific renderer, and loads of possibilities.
I do prefer Blender.But is not easy to learn, true.
Yet so, there's nice stuff in Anim8or, like the fact it has edge creasing for smoothing normals, setting an angle threshold (autosmooth in Max, do not mess with the subdividing concept! )
Blender has not got yet this.
An easy one...Neither have ever used...but probably is of the kind of simply3d.(I have that one)
http://www.freeserifsoftware.com/software/3dPlus/default.aspThough being from freeserifsoftware, seems no free register required
An old and a bit complex to handle 3d package, also free :
http://k3d.sourceforge.net/I find this one hard for a newbie, but hey, is free too :
http://openfx.org-Conclussion: go for Blender in first place, if you can't, for Anim8or. And if that one is yet hard, for that 3dserif plus or however it's called. Blender can't be learnt without the docs , there extremely good doc online at blender.org site. You can download too.Once you lear the general workflow is not so hard.