Also, with their forever refund policy, I think getting one via Costco is the right move.
It would be good to ask a sales associate to confirm whether their satisfaction guaranteed refund policy extends to SPOT devices - COSTCO rolled the term back to 90 days a while ago for computers, TVs, MP3 players and similar merchandise. I'm not sure whether SPOT falls into the category of merchandise they will redund on if you're not satisfied.