instead of a price, you’ve already purchased the item and you can download it again without a charge.Tap an item’s price (or tap Free), then tap again to buy it. If you see instead of a price, you’ve already purchased the item and you can download it again without a charge.
Use a gift card or code. Tap a category (like Music), scroll to the bottom, then tap Redeem. To send a gift, view the item you want to give, then tap 
and Gift.
See the progress of a download. Tap More, then tap Downloads.
Bought something on another device? Go to Settings > iTunes & App Store to set up automatic downloads to your iPod touch. To see your purchased music, movies, and TV shows, in iTunes Store, tap More, then tap Purchased.
Watch your time with rentals. In some areas, you can rent movies. You have 30 days to begin watching a rented movie. After you start watching it, you can play it as many times as you want in the allotted time (24 hours in the U.S. iTunes Store; 48 hours in other countries). Once your time’s up, the movie is deleted. Rentals can’t be transferred to another device; however, you can use AirPlay and Apple TV to view a rental on your television.