What is the ruling on purchasing prepaid Visa/MasterCard cards from stores, for use in online shopping, knowing that their full value is paid along with taxes, they cannot be reloaded, and they are used once until the balance is depleted?

If the card is purchased with its own balance, there is no harm in that, such as buying a card with a hundred-dollar balance for a hundred dollars. It is permissible to buy it with another currency, even if it costs more, due to the difference between the two currencies. If "Texas" is a name for the card, it has no effect. If it is a tax on purchases (other than food), paying it does not affect the permissibility of using the card.