Let's be frank: Greyhound stations and 7-Elevens aren't where most tech companies go trolling for customers.

But Mountain View startup PayNearMe sees gold in a market the financial industry has largely overlooked: the roughly 60 million Americans who don't have bank accounts or credit cards.

"It's a huge audience," said CEO Danny Shader.

Shader is a serial entrepreneur who sold one of the first online-payment companies to Amazon.com and later ran Good Technology, a mobile email provider that Motorola acquired in 2007 for $500 million.

His latest startup -- backed by heavyweights such as Vinod Khosla, August Capital and Starbucks CEO Howard Schultz -- began life about three years ago as a way for people to buy "virtual goods" in online games like "FarmVille."

Eventually, though, Shader realized the real world presents more opportunity than the virtual. Thanks to an arrangement with 7-Eleven, cardless customers now can use cash to pay dozens of merchants, send money to family abroad or shop on Amazon.

"We're seeing thousands of transactions every month, and we expect that to grow," said Raja Doddala, a senior product director at 7-Eleven headquarters in Dallas.

With about 6,500 stores around the country, the convenience store chain acts as PayNearMe's front-line retailer, although Shader is working to forge partnerships with others. Customers exchange cash for gift cards or wire transfers, and Pay-NearMe splits the transactions evenly with 7-Eleven.

Last month, the two companies rolled out a nationwide agreement to let people buy Greyhound bus tickets. A passenger books his or her ticket online, prints a confirmation bar code, then takes the code and cash to the nearest 7-Eleven. The register receipt serves as the rider's bus ticket.

Shader says he saw a dramatic spike in ticket sales for the Thanksgiving holiday. He also noted a surprising number of riders booking Greyhound tickets via smartphones.

In addition, residents of Fairfield now can pay utility bills via the service for a $2.99 convenience fee, and plans are afoot to offer that in more communities.

"We're open 24 hours; the city offices aren't," notes Doddala.

Also in the works, Shader said, is an app for landlords to accept rent payments via PayNearMe instead of money order.

His 20-person startup has notched about $23 million in venture capital. And while it may not be as sexy an investment as Facebook or Twitter, PayNearMe is helping boost the Internet economy, says August Capital partner David Hornik.

"Twenty-five percent of the U.S. population have easy access to the Internet but have no way to buy anything," Hornik said. "That adds up to a huge opportunity."

Contact Peter Delevett at 408-271-3638. Follow him at Twitter.com/mercwiretap.