If you're handy with tools you can build one from a used end table or wood.
I made Noah and Allie beds out of table legs, a small sheet of plywood and some 1x3's
These are fence posts, cut in half
http://i1199.photobucket.com/albums/...n/579af509.jpg http://i1199.photobucket.com/albums/...n/41bae743.jpg
these are table legs, ready made from home depot and turned upside down.
http://i1199.photobucket.com/albums/...n/43469e68.jpg http://i1199.photobucket.com/albums/...n/a57dbfed.jpg
I used handkerchiefs for the cushions ( 2 for .99 at the dollar tree). Noah chewed on his a little but a light sanding took care of it. They climb on them like monkeys but can't move them around.