Use your Citi Rewards Credit Card when shopping online or buying in retail stores. In most cases, you can earn 10X points or 4 miles per S$1. But if the item does not qualify for the higher reward tier, you still make 1 point or 0.4 miles per S$1. Do note that there is a monthly cap of 10,000 points per statement month. And, the points expire after five years.