I use 3ds max most of the time now; but it's probably not in your budget.
I did make quite a few transcendence ships and stations (and dockscreens) with a combination of Wings3d and Bryce. Those are both free, and they are both pretty simple to learn.
Here's links to some free modelers:
http://www.wings3d.com - Wings3d, polygon sub-division modeller. Easy interface, quick to learn.
http://www.anim8or.com/ - Anim8tor, pretty simple sub-d modeller and animation tool.
http://www.metaseq.net/english/index.html - Metasequioa, haven't used it; but know people that love it...
http://www.caligari.com/products/trueSp ... /intro.asp - Truespace Version 7.5
Truespace is a pretty solid all around 3d app. Used to cost around $800, I think.
There are lots of free modelers around, just google and do some digging.
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And free renderers:
http://www.download.com/Bryce/3000-6677_4-10696716.html - Bryce 5.5
http://www.kerkythea.net/joomla/ - Unbiased Global illumination (including MLT) renderer.
http://www.indigorenderer.com/joomla/ - Similar to Kerkythea.
There are some others around: POVRay, Sunflow, Toxic, and so on. Some of them are rather technically oriented, and not very user friendly.
Kerkythea and Indigo have plugins for integrated use with Blender. Blender has its own built renderer that does a nice job also.
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EDIT - If you are interested in using people for renders, you could look into DAZ Studio. Free base program, with purchasable upgrade 'modules'.
http://www.daz3d.com/i/software/studio?_m=d