Hi,
Depends, are you an experienced modeler? If so, do a search for graphics or 3d, as there are several extensive lists of free/demo modeling programs, and some even have excellent descriptions of their abilities. If you are experienced, and in need of a basic program, Eovie.com has just released Carrara basics for $99. I have not read all the specifics, but i believe it comes with everything needed.
If you don't have experience modeling, your best bet would be Poser, (url="http://"http://www.curiouslabs.com")www.curiouslabs.com(/url) I don't think it allows saving, but with Snapz, that problem is fixed. This also leads you to the problem of dressing your character, as Poser is, in short terms, an electronic Barbie/Ken set. So you would need to peruse one of the many Poser-related sites out there that offer clothing, props, etc.
I have assembled a rather crude listing of links for my own purposes, but being a nice guy, I share. In it you will find links to free models, textures, tutorials, etc, to help you on your way. (url="http://"http://homepage.mac.com/dampeoples/artlinks/stuff.html")http://homepage.mac....inks/stuff.html(/url)
Good luck
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Just pimpin' my (url="http://"http://www.thejbfc.com")fishing skills(/url),(url="http://"http://www.renderosity.com/gallery.ez?ByArtist=Yes&Artist;=dampeoples")gallery(/url), and (url="http://"http://homepage.mac.com/dampeoples/Sterling/Menu19.html")other stuff(/url)