Ah, okay. Well, there's nothing cheaper than free, so there's Walrus, which is open source, though still under development. It looks like it renders in 3D space, but it may not have all the manipulation features you want. H3 is another open source project that uses hyperbolic 3-space. That sounds cool. :)
aiSee is a free (for non-commercial use) graph browsing package that looks a little more polished.
