You are never more than a few hundred metres from food. Typical Singaporean food is eaten at street cafes - you shouldn't need to pay more than a few S$ and the quality is good.
maxwell hawker center in chinatown, hands down. go after 6pm to get your local grub on at local prices. top 5 are chili crab, laksa noodles, fresh fruit, sesame desert balls and satay sticks.