I thought it used to be an option that you could pick them up from your hotel when you arrived? You can always set everything up using your Disney My Experience app and then when you get there, purchase the bands and assign it to your account.
Under the My Experience App if you look at your settings and choose Disney MagicMobile, you can create cards that can be added to the "wallet" of your phone that can be used just like magic bands, in that they can open the door of your disney hotel and include your tickets and stuff. That way you have access to everything until you can get your hands on some bands.
I like to use a combination of both the card in my phone wallet and the magic band, as my 11 year old nephew cannot keep track of his magic band for the life of him and I always have access to his tickets and any ride reservations.