McMaster Carr told me they only sell to businesses regardless of whether or not it is in the US or Canada? What's that all about? Sounds goofy. This was their email: "Due to the complexity of U.S. export regulations, McMaster-Carr accepts international orders only from businesses. This decision also applies to orders shipping within the United States, because it is based on the final destination of the items. We are unable to provide a quotation or accept your orders."That's where I buy them as well.
Here is McMaster Carr link. http://www.mcmaster.com/#standard-filter-bags/=t2wjiu