Best Cheap acoustic wall treatments?

Put acousic tile on the ceiling. This is the largest unbroken area available for treatment, and is very effective. Also, an easy diy project. A nice rug on the floor, curtains for any windows, and a few upholstered pieces of furniture, and you are in business.

Geoffkait...I have found that ceiling times (of the proper variety) are amazinly effective for quieting a space...say an office in a noisy production area. I can't think why they would work differently from other types of room treatment, but then I haven't actually tried them. Thanks for the ":heads up".