Apple's Lion (v10.7) operating system, which was released in July 2011, brought some notable improvements to Mac App Store, allowing users to make in-application purchases and receive push notifications and adding an incremental update system that identifies, downloads and installs only the files that need updating, making the process faster [source: Porten]. However, the Mac App Store doesn't recognize updates for a computer's existing software apps; you'll need to re-purchase the apps from the Mac App Store to receive automatic free updates for the apps [source: Gordon].
Now that downloading and updating apps is an exclusively electronic process that doesn't require disks, packaging materials and shipping, there's less of an environmental impact. Additionally, many Mac apps sold via disk or download had limited permissions that allowed them only to be operated on a single computer. The chief way around this restriction was to buy a pricey group license. Because the Mac App Store keeps track of past purchases, users can now install apps on every Mac they own and download them again as necessary. This is especially helpful for people who buy a new Mac and want to add software that they've already purchased [source: Apple].
Ever tried to open a file and discovered you don't have the application it requires? On Macs with access to the Mac App Store, a dialog box will open and offer to search the Mac App Store for a program that will open it. If found, you can buy the app instantly [source: Luoma].
The Mac App Store offers free apps, as well as paid. On average, you can expect to pay between $15 and $80 for an app [source: Macworld]. However, there's at least one app -- the iRa Pro mobile video surveillance app -- that costs as much as $899.99.
What's the process for buying this -- or any -- app? On the next page, we offer a step-by-step guide.