Pre-paid card can be great for this sort of thing. Be aware of what fees are associated with the card. Some cards charge maintenance or other fees. All pre-paid cards are not created equal and some are better than others. The card you mentioned may charge a $3.50 a month if you have 12 months of inactivity. The initial fee for the card is $5 if you are not a bank member. Keep in mind that some pre-paid cards allow the holder to withdraw the cash which means you would not be able to track what the money was spent on. You can also look into credit cards that allow you to set spending limits and parameters for authorized users.