Well there is other programs such as Blender (an open source 3D editor) and Trimble Sketchup, which are free. But I'm currently using 3ds Max, and no I haven't payed for it incase you're wondering... I aren't rich. lol
But if you're downloading 3ds Max, make sure it's 3ds Max 8 with a keygen, not any newer version... 'cause the plugins won't work on newer versions.