First of all, there is no ONE simple software that will answer all your needs.

Some people (me, for that matter), stick to one thing (Poser 7 in my case) and build the world for their stories there. Photoshop helps with postwork later on.

Others render background in Vue or Bryce and then compose the scene in Poser.

Others export a scene from Poser to Vue or Bryce and there they render the thing.

Basically, as many Poser comic creators, as many ways of doing the actual comic. Go around the web. See which freebies or products look like those You could use for your comic. Make a list. See what software those freebies or products are for. See if it's affordable.

Search some more.

Looking at other people's Poser comics helps - if you see anything you like, you can always ask how it is done and what did they use. They will answer, most of the time.