Now Playing: 7-10-13 Marketplace Tech: Apple's App store turns 5

Five years ago today Apple's App store opened for the first time as an expansion of the company's online marketplace iTunes. On its first day, there were only about 500 apps available. At five-years-old, it offers over 850,000. This week Apple's been offering a bunch of its apps for free to celebrate. But that's not actually all that unusual. The complex ecosystem of apps has gone through quite a pricing evolution.