I have also used detox food pads a few times; can't say it did anything miraculous but had good experience with them overall. Felt they triggered some pressure points like reflexology and perhaps that aids toxins removal. I notice that the pads got lighter with usage (may mean that the dumping of toxins is reduced after initial purge).
I ordered them at http://www.purifyyourbody.com/ for like $1/pad. I've also used them here in Japan. They are widely available in every pharmacy and are affordable here (I love it that here there's no pharma ads but rather natural supplements and things that may be considered taboo back in the states like Colloidal Silver and other non-patentable products).
It's possible that the purging of toxins may also be dependent on circadian rhythm and moon phases so perhaps there may be a relationship with how well you feel with these dependent on those factors.