You can buy magazine subscriptions from Amazon. Essentially the Amazon cloud replaces the computer. You can read the magazines on Kindle without a special reader app, or on iPad using "Kindle for iPad" reader app, with no need for a computer with calibre. But you might have to specify which device at purchase. Not sure how it works since I've never done it. Here is the link for "Kindle for iPad":
http://www.amazon.com/gp/feature.htm...cId=1000490441