“Pain of paying” is a concept from Behavioral Economics that refers to the negative emotions experienced during the process of paying. Multiple research papers has found that credit card purchases are associate with lower level of pain of paying, comparing to cash purchases.

"Credit cards make you spend like a Kardashian."

The concept of Cardashian, a budgeting tool, came from the idea to substitute the lack of pain of paying when using a credit card, helping users to visualize their financial health in a intuitive way. Cardashian features a tomogachi-like pet credit card. When the budget is well-managed, the pet thrives, but if the budget runs out before renewal, the pain of paying directly inflicts on the pet. The credit card character is designed with bright colors and expressive animations, making it relatable and transform the mundane task of budgeting into a fun experience.