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No-line-of-credit debit card?
I think what you are looking for is a secured credit card. They are mostly used by people who have ruined their credit and want to rebuild it, but it might also serve your purpose.  Essentially you deposit some money in an account and the credit card can be used up to the amount left in the account. Each month when you pay the bill, it resets the balance that you can charge. Also, many credit card providers also offer "disposable" or "one use" credit card numbers for the express purpose of using it online. It still gets charged against your regular account, but you get a separate number that can only be used for up to X dollars of transactions.