How do you pay on Steam in a way that avoids using your card?
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You can buy Steam Wallet Codes in retail stores that sell them. They work much like prepaid SIM load cards where you uncover the codes by rubbing a coin on a special area which will reveal them. Afterwards, you can enter them into a page in Steam which will credit the pre-designated amount (such as a $100 Steam Wallet code) to your Steam Wallet.