Abstract: A versatile universal prepaid petroleum-related (e.g., gasoline and oil) and travel card system that features a pre-paid card that can be used at any major brand filling station. The card is encoded with data indicating its authenticity; and provision is made for optional encoding identifying it with a particular user, company, individual or event. The card is also usable for purchase of non petroleum-related products such as the sundries sold at many filling stations. The card, when purchased by a prospective user, can initially be pre-encoded with specific dollar amounts (e.g., $50.00, $100.00) or be blank and when purchased be encoded with an amount selected and paid for by the purchaser. Moreover, the purchaser may, at any time, increase the then-existing amount by paying for the desired amount of increase in cash. When a purchase is made using the card, a card-reader authenticates its authenticity and decrements the amount of pre-paid credit remaining on the card by the amount of the purchase.