The Cash Shop Loyalty Card, also known as a Rewards Card, is a feature added to Cash Shop purchases.
Each purchase of CSC through Paypal or Stripe will grant you a stamp for the card. 1,000 CSC will grant you one stamp, and it will be cumulative so if you buy smaller incrimants that add up to 1,000 in total it will grant you a small stamp. If you purchase 2,000 CSC you will get a large stamp.
Each stamp is worth a certain amount of Loyalty Points (LP) depending on how many stamps you have. If you have 1, it will be one LP. If you have two, it will equal 2 LPs. Filling up a card will reward you with 55 LPs, and an extra 5 for completing that card.
A new card is released every 3 months, and a total of 2 can be filled up each term - meaning a total of 120 LP for both cards completed. With each new card, new rewards are released.