The pack is free with the exception of the font, dungeon map and updated GUI.
I think you should be able to click "Buy Now" on the asset and you'll be prompted with the option to use either PayPal or Card. Both of which accept Visas.
Unfortunately, when I click on "Buy now", I only get a button with PayPal, which is not yet available in my country :C . Therefore, I wanted to clarify whether you have a card payment set up to buy this magnificent pack.