Bryce is free on 3D World magazine this month. But it's rubbish so don't bother.

BEST 3D modelling program is new - MOI (www.moi3d.com) - it's currently in free Beta and is made by a Rhino3D-defector. VERY easy to use & NURBS supporting (won't mean anything to you unless you're wanting to create solid objects for manufacture).