These 5 Start-ups Will Change the Way You Pay for Everything

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Google Wallet for Gmail

Square isn't the only company innovating cash payments with e-mail. Soon Gmail users will be able to do the same thing.

Even if your family and friends don't use Gmail, you can still send them money so long as the search giant has access to your bank account.

The service will be free, however, Google says "low fees" will apply for payments sent through credit or debit cards.