“We think this is a big one,” Marc Andreessen says opening up our call about his $15.5 million investment in ItsOn.

ItsOn totally reinvents how you charge for mobile services and who can pay for them. It aims to do two things that shouldn’t be compatible: Make more money for carriers and save money for end customers too. We’ll get into how both can happen in a moment.

But first, it bears noting that there are three levels of the Marc Andreessen endorsement these days, as his star has risen and investing docket has gotten more crowded. The first is, you know, getting the actual cash. Certainly, that’s the endorsement many companies should care about most. The second is his agreeing to hop on the phone with multiple reporters to talk about the deal. And the third is opening said call with a bold statement like that one above.

Put another way: In the compendium of the things Andreessen Horowitz invests in, ItsOn is near the top of a pretty competitive list.

What’s more: ItsOn doesn’t readily fit into buckets of other things AH is funding. It’s in the mobile infrastructure space. It’s a company that is so complex that it has taken four years of stealth development to get to the point where it’s finally ready to do a big commercial launch. That’s longer than birth to acquisition lifecycle for many Valley companies these days.

And — most damning of all for most startups — for ItsOn to work, it needs to ink make-it-or-break-it deals with carriers. Deals with carriers! What most of the tech world loves about how mobile has evolved is that you no longer have to do deals with carriers to get on the mobile Web, you just build for Android or iOS and go. “We have religiously avoided companies that have to do carrier partnerships,” Andreessen says. “This might be the only one we’ve ever done.”

So what makes ItsOn so damn special? Two things, Andreessen says. The first is the founding team. I know, I know, that answer is a well-worn cliche with investors, but it is usually the determiner when it comes to funding ambitious companies like these. The second was more simple: “We were convinced this has to exist,” Andreessen says.

Why? Because the farther Apple and legions of developers take the mobile Web, the more they are also breaking its infrastructure backbone. Developers don’t pay for the bandwidth their apps are using, they’re passing it onto customers, and customers have no real idea how much each app is costing them in data fees.

And really, the fees aren’t even getting passed on to the customers who are actually using the apps. Eighty percent of users are overpaying to subsidize what the real broadband hogs are consuming. As carriers’ capital expenditures balloon to more than $20 billion a year, and more and more stuff gets crammed onto our smartphones, something has to give. Particularly now that more than 50 percent of handsets sold are smart phones.

In other words: The mobile free-for-all is over, and ItsOn is trying to enable creative ways to make mobile networks profitable and sustainable, while keeping pricing fair for customers.  “If this continues the networks will collapse,” Andreessen says. “One approach is that everyone pays a lot more. We’re trying to avoid that.”

Instead, ItsOn wants people to pay for what they use. Using its software — that’s both a cloud platform and runs on individual handsets — users can pay for data services on the per app level. You can even buy use of an app for the day. Want to watch the Superbowl on your phone? You pay just for that. Want to buy your kids a day of Facebook if they finish their homework? You can do that and do it again tomorrow if they do their homework again. Your employer can pay for your consumption of Salesforce.com, while you pay to play Angry Birds. Or an advertiser could support any of those.

In the US, this gives carriers a way to better align costs and revenues. But there’s also a clear use case for developing nations, where granularity of services can allow more people to use the Web for the first time in affordable ways. And, it could allow for formerly dumb devices to become connected, and offer new services for no charge to consumers. Imagine if a maps app in your car was brought to you by Google, no wireless charge necessary.

This kind of slicing and dicing of data plans has never been possible before.

And to that cliche point of Andreessen Horowitz backing the team, few others could pull it off. ItsOn was cofounded by Greg Raleigh and Charles Giancarlo. Giancarlo is most known for leading Cisco’s product development for a decade, and Raleigh invented and commercialized parts of 4G and the newest WiFi technology. He founded Clarity Wireless which was acquired by Cisco and Airgo Networks which was acquired by Qualcomm.

They are people who intimately know the problems, how to solve them and how to actually sell to carriers.

For Raleigh in particular, the company is the culmination of his career’s work. “The first thing I did in mobile wireless was 4G,” he says. “We didn’t have connections fast enough to enjoy the mobile Internet the way we can on PCs. But once you fix the connection, you still have problems with networking and service. Everyone saw this coming but no one had a good solution.”

And because it’s all software, ItsOn is able to have a huge impact on the mobile industry with far fewer employees and expenses than Raleigh’s previous companies. “I think this could be even bigger, and because it’s all done with cloud technology, we can do it with a very small group of people,” Raleigh says. “Airgo had ten times as many people as we have now.”

Having done trials with some 20,000 consumers around the world, ItsOn is ready to launch and has a few commercial deals in progress, and more in the works. But — at least now — it won’t be on any iPhones. Raleigh wouldn’t comment on specifics to partnerships, but Andreessen characterized iPhones as considerably more “complex” to deal with than Android devices. “More on that in the next phase of our roll out,” Andreessen says.

[Disclosure: Andreessen is an individual investor in PandoDaily.]