Money orders are guaranteed, unlike personal checks. Checks can bounce. Money orders, unlike cash, allow you to specify the payee.

A bank or credit union sells money orders. Western Union, USPS, convenience stores, pharmacies, payday loan stores, and Walmart sell them.

People use money orders when they're uncomfortable paying with cash or a check, or when the recipient doesn't want cash or a check.

Cash is stolen. Personal checks may not clear, so a company may not want to accept them. Sending a money order eliminates that concern.

A thief could steal your mail and take a money order, then exchange it for cash. Money orders aren't easy to steal.

Jenny Chang, a 34-year-old PR executive in New York City, recently moved into a condo with a pool. "Each summer, residents must pay $25 for a pool ID," she says.

Gutierrez recommends using apps. This year, he started sending money to his family via phone apps. He uses Paypal's Xoom and Remitly.com.

Xoom and Remitly have fees that vary by amount and country, but they're comparable to money orders, Gutierrez says.