Purchase a prepaid credit card. Many financial institutions, as well as check-cashing establishments, offer them. You can also purchase them directly online from most major credit-card distributors, including Mastercard and Visa. You may want to compare a little before purchasing a card; all prepaid cards carry fees and service charges. Pick what you feel is the best for you. (If you acquired a prepaid credit card as a gift or for some special occasion, this is obviously a step you can skip.)
Go to a store and pick out whatever you want to purchase. Keep in mind that the card has a balance you cannot go over. Present the card for payment. Many retail establishments have credit-card machines that allow you to swipe the card yourself. Depending on where you go and how much you spend, you may or may not have to provide your signature or picture I.D.
Use your prepaid card to pay for gas. Many gas pumps have a "pay with credit" option right on the pump. If you choose to do this, get out of your car and follow the directions on the pump. Most pumps allow you to swipe your card at the pump, much as you do at local merchants. You may need to input your zip code as verification of identity. Attendants inside the station will assist you if you need help.
Buy items online or through eBay using your prepaid credit card. If you intend to shop through eBay, register your credit card with PayPal to make sure your payments are fast and easy. Most retail merchants also prefer credit cards. When paying for your purchase, give them the credit card information on the appropriate online form. Most merchants have secure sites, so you don't have to worry about giving your personal information to someone who may attempt to harm you.
Pay bills with your credit card. Many paper bills have a space you can fill out with credit-card info, and it's almost always an option if you are paying online. Just click on "Pay My Bill Using a Credit Card" or something similar and type in the appropriate information.
Keep track of your balance. When the card runs out of money, you can no longer use it. You can, however, reload it by going back to the financial institution you purchased it from, or replenish it online using your bank account or another credit card. You may even be able to reload it over the phone. If you find yourself at a store with not enough money on your card, most merchants will allow you to use the balance on the card and then pay the rest in cash.