Wow! Great idea, great mission. Someone smart and well advised solving serious problems for real people who need help, that makes me happy.<p>My 2 cents: as you want to preserv their sense of autonomy, please use a card design that looks like an usual credit card. The "Visa" is already there, so just use some of these typical shiny, fancy, "3d" background designs of the credit cards we all get used to.
If your card is like the one at the picture on the landing page, it looks like a "toy card", something you give to children to pretend they have credit cards. Your customers will notice it and feel their son just substituted their real credit cards for make-believe ones.