Did the App Store just take a dollar from me?

Hi, I recently purchased a 15 dollar iTunes gift card and as soon as I had the opportunity, I went to purchase about 4 apps. However, when I went to download Jet Set Radio, it told me that I did not have enough money to purchase that app. Which is strange, because the apps I were purchasing were $5.99 (Surgeon Simulator), $2.99 (Sonic the Hedgehog), and again $2.99 (Sonic the Hedgehog 2). Jet Set Radio was also $2.99, and this total adds up to $14.96. I don't see how a card with a $15 balance was unable to purchase those four apps. If it means anything, I did already have $0.20 remaining before I entered the card in.

I'm not sure if iTunes has any sort of payment fee or something (which would be rather silly, if you ask me...), but it's really upsetting that I've been robbed one dollar before I could purchase an app I was really looking forward to using. I am also using an iPad 2nd generation, and I am unsure if I may have misread some of the prices for those apps. I am very disappointed about this.