Well if you are really that nervous about buying them in person you can always order online, even if you dont have a cedit card or paypal. Just go out and buy a prepaid visa/american express gift card. I can confirm they work on Xp medical's site, ABU, and secure X plus, though bambino wont work unless the card lets you input and address (most don't). Of course this only is an option if you don't worry about others opening your mail. As for sizes you can look that up before hand online if you know the brand.