For Newsstand is best to provide issues via download from your server. Don't bundle them with app, because that would require app review every time you add an issue.
For paid magazines, you have to create non-consumable in-app purchase for every issue. Then you can host your content with Apple if you don't want to use some CDN.
Still you'll need some kind of web service to:
- provide list of issues for iOS app
- provide issue content
- send push notification when new issues are available
- provide Newsstand feed to automatically update issues visible in the App Store
- validate receipts from the App Store
Simplified "algorithm" for a paid magazine iOS app would look like this:
- Fetch current issues from server and synchronize with local copy
- Fetch issue prices from App Store (create SKProductsRequest for every issue)
- Present issues to the user
- When user performs purchase, validate receipt and start downloading content
- If user purchased subscription, allow access to all issues for free (but keep checking if subscription is still active)
If this is too much work, you may want to use some existing solutions (disclaimer: I cofounded Issue Stand and am moderating this list).