Paying with your phone is easy.
Apple users can enable Apple Pay on newer devices like the Iphone 6, 6s, and Apple Watch.
Add debit or credit cards to wallet, then authorize payment using Touch ID.
Apple Pay is available at contactless terminals, and in some apps.
Android users have Android Pay, which works in a similar way.
Download the app, enter a debit or credit card and unlock your phone to pay.
Not all retailers have contact with terminals so Android and Apple Pay can be limited.
Samsung Pay is an option for Samsung Galaxy owners and works at almost every retailer Hold your phone against a terminal and it emits a magnetic signal that emulates swiping with a card.
Don't forget to check with your bank to make sure they support one of these mobile payment systems.
In San Francisco, I'm Lexy Savvides.
CNET.com for CBS news.