...and sales tax is different for different classes of product in the US, with some things getting better treatment, such as groceries, and some things worse, such as car tires. I did not expect it to be relevant to this specific case, but yes: I guess children's clothing is an interesting one for this Regretsy charity drive; that said, they stated "toys", not "clothing", and I don't remember toys being on that exemption list (which I actually have read, as I needed to see if any of the things I was selling had different rates).

(PS: the coolest one I've seen is that bound physical books often have much better tax rates than other goods, leading to hilarious situations where shipping someone a physical pamphlet that includes base64 might be much cheaper than selling them an expensive piece of software on CD. ;P)