I am buying a new house and need a relatively simple freeware CAD package that I can layout the lot and the house placement on the lot.

The house floor plan will come from a set of different plans the builder has used in the development, but I can optionally make structural changes to them. I would like to also be able draw the standard floor plan and then try differnt changes to see how they flow.

A grid background and user intuitive interface would also be nice. Does anyone know of a good freeware package for doing this? I bought a cheap CAD package for this previosuly, but threw it away as it was worthless and I don't want to waste money again on something I can't use.