Open iTunes Look at right side under quick links theres redeem click it, type in code, get app Not hard.
Copy the code, go to your iTunes application, click on the redeem link in the upper part of the right-hand column, paste the code in the blank space of the redeem page, and voila, your app should start to download. You can also redeem codes directly on the iPad, by clicking the redeem button at the bottom of the main page in your Apps application. You then follow the same cut and paste procedure, or you can of course type in the code yourself. Hope this helps !
So if I use a promo code on one device like iphone what happens if I try to buy the same version on the ipad (not hd)? Will it say you already purchased it and ask for a free download or charge me? Lets say its uder the same apple id or username?
It will say that you have already purchased the item and ask if you want to download it again for free. I do that all the time--buy it on my Touch and then also download it to my iPad.
As long as both devices use the same itunes account, it will say the download is free on the second device.