Am not able to complete app purchase on Macbook Pro

Every time I try to purchase the app aperture it has me login and confirm my billing info over and over again. I've exited out of the app store and tried to purchase the app several times and each time it comes up with the same thing. I have a gift card hooked up that I'm going to use to purchase the app and it's more than enough money. I am able to update apps and download free apps without this occurring but each time I try to purchase one I run into the same problem.