These days, consumers are paying for stuff by waving, sliding or tapping their smart phones.
That's because more and more apps are offering different ways to pay.
They're called digital wallets.
Maryssa Menkin is paying for her salad using Square Wallet's free application.
The digital wallet app links to her credit card, which she finds very convenient.
"I hate carrying a lot of things and, you know, I find that I do always have my phone on me, so it's just very simple," she said.
Starbucks is one of the hundreds of thousands of businesses nationwide that have signed up for Square Wallet.
Square is compatible with a number of iPhone and android models.
Consumer Reports money adviser Amanda Walker said it's pretty easy to use.
But other digital wallets are not as widely accessible.
Some digital wallet apps will only link with a few select credit cards.
So you may need to link to a prepaid card, which can incur additional fees.
That may also mean you don't have the best protections if you lose your phone or someone breaks into your account.
"Prepaid cards, whether in your hand or on your phone, have no guaranteed protections against unauthorized transactions, so you could lose whatever balance is on the card," she said.
But if, like Maryssa, you like leaving your bulky wallet at home, Consumer Reports said use an app like Square that links to a credit card for the best consumer protections.
Be sure to report a lost phone or suspicious activity to the credit card company right away and, of course, also inform your cellular carrier, so it can disable the phone.