Скачать или смотреть How to cancel or change Magazine subscriptions on itunes newsstand

If you want to do it on your PC/MAC via itunes program to simply stop any Automatic renewals in the future.

1) open Itunes program
2) across top left you will see some categories SELECT "STORE"
3) Then "VIEW ACCOUNT"
4) now log in with your Apple ID password
5) you will see a list of account information, you may now need to scroll down.
6) There is a box called settings. 5th item down is called subscriptions there you will have a number this is the number of subscriptions you have. If this is 0 then you have no subscriptions.
7) Click the blue "MANAGE" to the right of subscriptions
8) you will see a list of all you subscriptions with an EDIT option next to each subscription. from here you can cancel or activate them.