If you do not have a Social Security Number for your dependent, and your dependent qualifies for a Social Security Number, you need to file a form SS5, Application for a Social Security Card (downloads as a pdf), with the Social Security Administration (SSA).

FORBES: Ask The Taxgirl: Social Security Numbers for Dependents

The application, which can be downloaded for free, charges vendors a credit card processing fee of 1.8 percent plus 15 cents per transaction, assuming you're swiping plastic from MasterCard, Visa or Discover.

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