He did it, however, without ever digging into his pocket for cash or a debit card.
Instead, the iPhone 4S in his pocket activated a tab on the food truck's iPad that's equipped with an application called Card Case. The clerk tapped on the tab and said thanks, and Frank left with his snack -- and with the $7.25 charge automatically added to his debit card.
Innovative mobile-payment technology is rapidly turning smartphones and tablets into virtual wallets and cash registers, changing how merchants manage their businesses and how customers pay.
"This is an awesome alternative for buying stuff you want without having to worry about having enough cash on you or pulling out your debit card," said Frank, a University of Central Florida student who downloaded the Card Case app last week from a company called Square. "It's also a cool way to impress your less tech-savvy friends."
Mobile payments are expected to boom as the holiday season kicks in this month.
A survey by the National Retail Federation shows that half of those who own smartphones will use them during holiday shopping. Another study shows one in three retailers has iPhone apps, while a smaller percentage use Android and iPad apps.
Intuit in 2009 launched GoPayments, which uses a device that plugs into the headphone jack of a smartphone or iPad and is used to swipe credit cards as a form of mobile payment.
Many businesses have flocked to this product because of Intuit's experience and dedication to security through its other well-known products such as QuickBooks, Quicken and TurboTax.
Twitter creator Jack Dorsey debuted Square in 2009, and it uses a similar gizmo. Square's Card Case app enables customers also to store digital receipts and search nearby businesses using the software.
Both Square and GoPayments have worked out deals to charge merchants a flat fee for running MasterCard, Visa, American Express and Discover payments.
Square takes a 2.75 percent cut on every swipe, while Intuit charges merchants 2.7 percent. There are no monthly fees, and the devices are free.
Tony Adams, owner of Big Wheel Provisions, said the low cost was a great incentive for using Square, but its acceptance among Orlando residents is the real benefit.
"Orlando has a really strong tech and computer-literate population that is open to this new type of technology," Adams said. "All merchants really need to look into Square for their business platform. It really simplifies things."
But the technology isn't just for mobile businesses.
Apple this week updated its Apple Store app to allow iPhone users to purchase a MacBook Pro, iPad 2 or other select Apple products on their phones and pick them up at their local retailers.
Google Wallet, which launched in September, is a mobile-payment system that allows users to store credit cards, loyalty cards, gift cards and sales promotions on their smartphones. It is popular among brick-and-mortar establishments such as Guess, Macy's, Bloomingdale's, American Eagle Outfitters, Best Buy, 7-Eleven, CVS and other businesses.
Users tap their smartphone equipped with the app on the PayPass reader of businesses offering the service. The smartphone then deducts the payment from the user's credit card.
The downside to Google Wallet is that it only works on Sprint's Samsung Nexus S 4G, and users must have a Citi MasterCard or a virtual Google Prepaid Card.
Still, some Central Floridians say using their smartphones to purchase goods is easier than fishing in their pockets for their wallets.
"I'm always holding a bunch of things in my hands, and one of those is my cellphone," said Fernando Mercado, who uses his Google Wallet at Pollo Tropical in southeast Orlando. "Our smartphones are constantly within reach. We're already using them for more than just phone calls. Why not use it to pay for our food, clothes or whatever? It's handy and quick."
Our new comment system is not supported in IE 7. Please upgrade your browser here.