To download Quicken, you need to buy the downloadable version of the software from Quicken.com, Amazon Appstore or Mac App Store as of 2015. After buying it from Quicken.com, navigate to the website, click the Sign In link at the upper-right corner of the page, and click My Account. Enter your email address and password to sign in to your account. Once signed in, click Downloads & Unlocks on the left sidebar of the page, and click Download beside Quicken.
To buy and download Quicken from the Amazon Appstore, navigate to Amazon.com, and enter "quicken" in the Search text box. Click the Quicken edition you want to buy, select the Download platform, and click the Buy button to buy the software. Once purchased, navigate to Your Games and Software Library in your Amazon.com account, and click the download link to download the software.
To buy and download Quicken from the Mac App Store, open the Mac App Store app, and enter "quicken" in the Search text box. Click the price for the Quicken app, click Buy App, and enter your Apple ID and password to download the app. To download a previously purchased Quicken app from the Mac App Store, open the Mac App Store app, and click Purchases at the top. Click the Download button beside Quicken to download it.