You said CHEAP, right? I built this one with a few feet of speaker wire and a few wooden sticks glued together. Slips nicely hidden behind my entertainment unit, though it is directionally sensitive. You can also build one right on a wall by wrapping around nails... read the directions and you'll see what I mean. couple of links to same project - one has an animation that helps you visualize the design.
http://www.wryr.org/Antenna_instructions.pdf
http://www.zbconline.com/antenna.html
http://www.zbconline.com/3dantenna.html
http://www.wryr.org/Antenna_instructions.pdf
http://www.zbconline.com/antenna.html
http://www.zbconline.com/3dantenna.html