Hello,
I have an iPhone 5 that I upgraded to ios7 earlier this month. I was looking around the App Store and noticed that iWork is "free", I thought this was only for new devices, say, if I bought a 5s. Will I be charged if I download these?
If you download it for free today under your Apple ID, you will always be able to re-download it for free again in the future on any new iDevice you get under the same Apple ID.