Laas said LearnerNation is trying to raise $750,000 of fresh capital and would use some of the funding to hire a Miami-based chief technical officer. The company is seeking “a mid-level programmer that can come in and know our programming language,” he said. “I would say we are willing to pay anywhere from $60,000 to $80,000 a year.”

Despite good pay for full-time work, talented software designers and developers often prefer to work on their own, and many have gravitated toward app development for mobile phones. David Elgena, for example, is an entrepreneurial software designer in Miami whose professional claim to fame is a popular application for the iPhone. The 28-year-old initially doubted the viability of the iPhone when Apple introduced the handheld phone-inside-a-computer in 2007, launching a new era in mobile app development. “I just thought nobody wants this much stuff on their phone, but I was wrong.” Now Elgena has the right take on the mobile connectivity trend and the sales revenue to prove it.

In the first two weeks after Weather Dial, his iPhone app for real-time weather reports, appeared in the App Store, Apple’s online shopping site, more than 20,000 buyers paid 99 cents each to download it. He has updated Weather Dial and raised the price to $1.99 since its initial release last year. “It was kind of like disbelief,” Elgena said, describing his initial reaction to the surge in sales of his app. He once worked full-time for Senzari, a software firm that provides Internet radio service with offices in Miami, San Francisco and Berlin, Germany. But his solo success encouraged him to resist working full-time for others and pursue his own professional path.

“In the beginning, it was hard to establish the self discipline,” he said. “But now I think I’ve got the hang of it. Just waking every morning creating new products, which is what I love to do.”

Welcome to the independent wing of the app economy. Elgena, a recent graduate of Miami International University of Art and Design, is a sole proprietor out of choice, not necessity. He has had his share of full-time job opportunities. “I interviewed at Yahoo! at one point to join their mobile team. That didn’t work out,” said Elgena, who operates at Pipeline, a shared work space in Miami’s Brickell financial district. “But there have been a lot of inquiries.”

Successfully developing a mobile app is inexpensive because distribution costs are low. Downloadable mobile apps are just clicks away online at such shopping sites as the App Store that Apple. operates. “The App Store has aided my success,” Elgena said. “It certainly has made it easier for me as an individual to distribute to a wide market.”

The worldwide number for mobile app downloads will reach 108 billion by 2017, compared to 60.1 billion last year and 29.5 billion in 2011, according to a new study by Sweden-based telecom consulting firm Berg Insight. The firm also forecast that Apple’s App Store will remain the No. 1 online source for mobile app downloads, followed by the No. 2 shopping site, Google Play, and Windows Phone Store in third place.

Even small improvements to existing computer applications can produce big rewards. Elgena, for example, redesigned the look of the typical weather app, the user experience, rather than reinventing it. He paid almost $5,000 to a third-party software developer in Ukraine that did certain types of coding to make Weather Dial work. “As far as the very heavy, back-end coding, I haven’t learned it, because I realized my time is more valuable on the front-end design, creating the user experience,” Elgena said.