^ This is an easy one
I use Poser for my figures, a program that is designed more for static and animated 3D images, but not modeling (you buy or download figures for it); for the latter, you'll need a program like the several mentioned in this thread (Blender, Maya, Lightwave, etc.). Poser is relatively cheap at $249 from www.e-frontier.com
, but DAZ 3D
has a similar program, DAZ|Studio, for free (it will not do animation, however). For what you want to do, I'd probably try DAZ|Studio; you can also find a great deal of free Poser content out there, most of which will also work in DAZ|Studio, and if you have Photoshop or pretty much any other bitmap editor, you can create new textures, bump maps and transparency maps for existing clothing which can help you in your quest
. I'd also suggest looking around at Renderosity
, which has a large Poser community, with both a marketplace and thousands of free items, as well as fora and tuorials.