Most renderers are available for use at no cost one way or another. But of course, there’s almost always some restriction.
The best rendering software program that fits the bill is Blender, which is totally free.
3ds Max, Maya, and Revit, among others, have an exclusive free edition for students and educators.
Lumion is available for trial use for 14 days only.
And V-Ray would be refundable if you cancel it within your first two weeks of subscription.