I think I've seen them advertised in catalogs from places like,
http://www.uscav.com
http://www.cheaperthandirt.com
and place like them.
If you know anyone that works at the places where they are made, you can get them by the truck load, just factory seconds for cheap...
When they are packaged up, they are weighed, and if they don't weigh out (something left out), the government won't accept them... so they get sold out the back of the plant...
We have a plant about 50 miles from us, and I know a couple of people that work there...
(They are always trying to feed us that crap when we are down that way! Yuck!)