Mojoworld would do the same (using moons) but it's over the $100 limit. There's a trick (tutorial) in Terragen (planetside, and free for the sub-V2 version) that makes a 'low orbit', which is a lot under $100. Bryce (5.5 should still be free, should be a link in the Bryce forum) can do planets of a certain size, with the right material.

If you have Photoshop, Flaming Pear has some planetary filters, or skins, or whatever they're called...;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)