Lucky Credit 

No cash, no credit? No problem! Haejun Do is trying to help his sick sister get into a clinical trial when he meets Seogyeol, the owner of Lucky Credit. This strange company issues credit cards to those with poor credit and who are unable to use normal banks, but there's a catch: instead of money, you have to pay with your luck. (Source: Manta) Note: Chapter count includes two extra chapters.