Is there free or inexpensive software to help envision furniture arrangement in a room?

I just bought a new condo. It has a cool, but unusually configured living room. I have some furniture, but will probably add a few more items. Before I buy them, I would like to try to imagine what it would look and function like. I am pretty “visual” and simply standing in the room is not helping much. I am sure in my circle of friends there is somebody with an eye for decorating, but I would at least like to give myself a start.