Singapore is a very expensive country for most things. I am finding that food and other things in the downtown and tourist areas are at least double, but it also depends on what you want and where you go to find it. Singapore is known for its marvelous food. The variety of foods you’ll find include: Singaporian, Maylay (Malaysian), Indian, Vietnamese, Indonesian, Korean, Chinese, Sri Lankan, Thai, and lesser amounts of Indonesian although it is really close (we will just go to Indonesia I guess) and more. This is also home to China Town and Little India.
For prepared meals, you can experience fine dining at elegant restaurants of many different cuisines (I hate to guess the cost), to wonderful, traditionally prepared meals, Asian mostly, at Hawkers Centers with 20-50 food vendors (some are open air with roofs, others are indoor, less slick versions of our mall food courts). But Hawker Centers tend to be in shopping centers or neighborhood based. For American franchises, there are KFC, McDonalds, and I think Subway, but I haven’t more than a couple of each. However, Singapore has too many Starbucks here.
For raw ingredients, Singapore has wonderful Fresh Markets, similar to our Farmers’ Markets, they also have roofs, open 7 days a week, and often until midnight. One booth sold beer by the bottle (better than the bars that charge $10+ for a beer). They are a great way to get authentic ingredients. Also, there are large grocery stores in neighborhoods that are pretty reasonable, outside of the tourist areas. Nearly if not all malls have big grocery stores in the basements.