To avoid buying or giving an empty card, only purchase gift cards from secure displays or from stores that load the card with its value at the checkout, advises Mark Huffman of ConsumerAffairs.com.

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One big red button sits between an empty SD card and a world of memories.

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Both agree that geology is a strong card: there is thought to be enough space to store billions of tonnes of carbon in empty oil and gas fields alone, and far more in subterranean salt caverns.

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