Another mom just called me up and asked about buying good beanbags in Ottawa - i had a few suggestions, but making your own is an option too! Check the link on how to make your own juggling beanbags. You can use rice, beans, or even sand.
Keep in mind to size the balls to fit whoever is juggling. I have giant hands, so i like a big beanbag. Kids have smaller hands, and they need smaller beanbags.. size appropriately!