I got mine at walmart in the rubber made section and I have an xl bummis bag in it too. Works great and the pail was only about $6. I also have a smaller one next to my bed so at night I dont have to go down stairs to put the dipes someplace. That one was at walmart for $3.
I use a big ol' Sterlite can too - only I don't use the lid on mine. I use a Bummis bag as well - but I like the bags on This Old Bag a lot - *great* prices! I need a couple more too - so I think I know where I'll be getting them!