If you subscribe to a monthly plan, you'll be charged for the content you download and any applicable data usage on your next invoice. When downloading games, you're charged for the download only, not each time you play.
If you're a prepaid service customer, make sure your account has sufficient funds to cover the cost of the downloadable game, ringtone, or wallpaper, as well as the associated data usage charge.
Taxes and other charges are not included.