Does applications movable to other iphones? I am fun of buying apps and not to jailbreak my iphone so all my apps are paid. Moreover, I am subscribed to deals websites, where I receive some newsletters with apps discounts or even paid apps to free for limited time.

My question is, all paid apps can be re-downloaded with no cost to a new device (e.g iPhone 6 when it will be out) ?
Moreover, those apps that was paid but was on free discount for limited time, are these apps free again to be sync to a new device?

Thank you in advance.
Once you have purchased an app from the App Store (even if it was free or discounted at the time) you can then redownload at no cost on your other devices so long as you log into the same Apple ID when you go to the store to download.  You can also sync from the same iTunes library, so long as the library is registered to the same Apple ID.