Buying and Downloading Media from the iTunes Store
When you select multimedia content in the iTunes Store, you can purchase the items and download them to your computer immediately. To buy and download content, you just need to click the Buy button, regardless of whether the item is a song, an album, a TV show episode, or an audio book.
For example, if you select a song in the List pane, click the Buy Song button in the far-right column for the song. (You might have to scroll your iTunes Store window to see the far-right column.) When you select a TV show episode, click the Buy Episode button in the far-right column. You can also click the Buy Album button in an album advertisement.
Purchasing content from the iTunes Store is a simple process:
Click the Buy button for the content that you want to purchase.
The iTunes Store may prompt you to log in to your account after you click the Buy button (unless you just recently logged in).
Enter your Apple ID and password, and then click the Buy button.
iTunes displays a warning dialog box to make sure that you want to buy the item.
Complete your purchase by clicking the Buy button in the dialog box, or click the Cancel button if you change your mind.
After you click the Buy button, iTunes downloads the item and, after downloading, it appears in your iTunes library.
You can continue buying items while your purchase item downloads, and because you already logged in, the iTunes Store complies immediately without asking again for a password. The iTunes Store keeps track of your purchases over a 24-hour period and charges you for a total sum, rather than for each single purchase.
You can see the list of all the items that you purchased by selecting the Purchased playlist under the iTunes Store option in the Source pane. The List pane changes to show the items you purchased.