When I first began using my iPad with iTunes I did not have a credit card associated with it. I downloaded tons of free apps before getting an itunes card. When I custom ordered my Mac air I used a credit card. From then on I had a credit card on my itunes account. While making iTunes purchases, I always use iTunes cards I began getting prompts to update my credit card info security number. I just changed the credit card info to none and haven't been prompted since. I usually look for iTunes card deals. Recently I was able to buy 25 dollar iTunes cards at Gamestop for 20 bucks. Sometimes a get 3 pack of 10 dollar iTunes cards for about 27 bucks. All this started when I got my iPad 1 so perhaps things have changed since then?