Mobile CPMs are falling fast, Advertising Age reports. According to industry executives, the cost of reaching 1,000 consumers on their mobile phones now averages $15 compared with an average earlier this year of $20 to $25. Last year, $40 to $50 CPMs were normal. "It seems to be part of a steady decline rather than a single event that sent CPMs tanking," says Eric Bader, managing partner of Brand in Hand, which buys mobile media for such clients as Procter & Gamble, General Mills and Esurance. So what's with the drop? Advertising Age's Rita Chang says the economy is a factor, as is "the onslaught" of new mobile inventory thanks to the proliferation of mobile applications. "As more advertisers leverage mobile and remove its mystique, the market will get more adept at pricing, and arbitrary pricing will give way to a broad range of CPMs that vary in their targeting granularity," Chang says. That's all good for mobile marketing's future growth, says Lars Albright, VP of business development at the mobile ad network Quattro Wireless. "The industry has matured quite a bit in the last couple of quarters to become a more efficient marketplace. One of the trends we're seeing is that the range has expanded and you can have everything from a low CPM all the way up to a mid-30s CPM."