Or any virtual mailbox, except Amazon lockers can only be used for Amazon packages (unless your place happens to have Amazon Hub). And I do admit postage stamps

Or any virtual mailbox, except Amazon lockers can only be used for Amazon packages (unless your place happens to have Amazon Hub). And I do admit postage stamps will add some bits of entropy in terms of datetime and country (couldn't find a list of countries Amazon lockers are located), though much less accurate than a monero or amazon transaction.