This work between certain states. For instance, you can drive into Oregon and shop with no sales tax then return to California or Washington with your goods.
Liquor is also much cheaper in some states than others—you can really stock up if you are already driving through a state.
I’ve carefully unsubscribed to everything with PaperKarma. Now I schedule a trip to my mailbox each Sunday. It shares a few package delivery boxes and I don’t want to accidentally monopolize one too long.