Like most Hilton Head Island Smoothie Co. customers, Doug Spade was confused at the cash register.
"So how much does this cost?" he asked Thursday, scanning the wall behind the counter. "I don't see any prices."
"It costs whatever you want," said store co-owner Marty Crocker.
Looking flummoxed, Spade handed him cash.
"It's like they were staring into my soul, man," Spade said after he paid $8 for a strawberry smoothie. "You'd feel guilty if you didn't (pay). I figured there had to be a catch."
There's no catch. The smoothie store on Palmetto Bay Road lets customers pay what they want.
"It's not that we're not charging," co-owner Alex Jasper said. "We're just allowing people to decide what to give. We want to take the transaction out of the equation."
Apparently it's working. Since starting the concept two months ago, Crocker said smoothie sales have dipped 10 percent, but profits have jumped 15 percent.
"I could see it going well in an area like this," said customer Robert Keller, who was vacationing from Atlanta. "It seems like a noble, egalitarian concept that people could get behind."
Employees say they rarely see a customer take and not give. Along with smoothies, the shop offers kale chips, yoga lessons, back massages and life coaching, among other goods and services.
"Sometimes it's a dollar, $10, then someone buys a $100 bag of banana chips," Crocker said.
The concept has been tried before. Panera Bread experimented with pay-what-you-want in some metropolitan markets. The English rock band Radiohead allowed fans to name their own price tag for an online album release.
Spokeswomen for the Hilton Head Island-Bluffton and Beaufort chambers of commerce were not sure if the concept had been tried before in Beaufort County.
For Crocker and Jasper, the pricing scheme is a philosophy.
Crocker, who has taught yoga for nearly two decades, said he hasn't charged customers for a class since 2005. He brings a basket to yoga sessions and lets people toss in what they please.
Jasper worked for 15 years in the corporate world. He quit Bluffton-based BFG last August when he grew tired of the "for-profit model," he said.
They acknowledged that some customers didn't quite understand the concept.
"Some people look at us real weird, and we know they'll never be back," Jasper said. "Some people say, 'I accept you.' Others just tell us we make a good smoothie."
Sandi Shriner, visiting the shop with daughter Caley, said she enjoyed the "different experience."
"I just hope I paid enough," she said.
Asked what would happen if they don't make enough money, Crocker smiled.
"We'll close. And we'll move on."
Follow reporter Dan Burley at twitter.com/IPBG_Dan.