Just to clear up misconceptions, there are mall food COURTS as opposed to food FLOORS of malls which tend to be full of chain restaurants. At the food courts, you generally have to preload a stored-value card which you must use to pay for the offerings. You can get unspent credit refunded on your way out. At Terminal 21 (at Asok BTS), the “Pier 21” food court on the 5th floor is arguably one of the best values in the city. When they were putting it together, they offered concessions to many of the top street carts or shop house eateries — and the food there is excellent and mostly freshly prepared. As for eating for $4, well I usually load the card with 200 baht and get at least two dishes, a small bottle of water and some leftover baht on my way out. If I want mango with sticky rice (yes I DO!) I need to put 300 baht on the card.

Just a few blocks or a 10 minute walk up Asoke Road is the Ruam Sab Food HALL or “market” which is a big open space full of stands offering all the Thai classics — chicken or pork stir-fried with holy basil with rice and an egg on top (pad krapao), chicken with green curry, green papaya salad (som tum), pad Thai, noodle soups to name a few — and a large area of benches and tables to chow down. There, you really can get a couple dishes with rice and a water for 60 baht (less than $2). The pad krapao lady is justly renowned as one of the best in the city. This place is aimed at the lunch crowd, so you need to go there from 11:00 to 13:30. At 12:30 it’s packed. At 14:00 it’s sold out. https://maps.app.goo.gl/nLhTAuiputae8Tiy8?g_st=ic

And another option: the food courts in SUPERMARKETS. The big supermarkets and hypermarkets like Lotus’s and Big C all have mini-malls surrounding the big store and many of those have very good and cheap food courts. As an example, we were shopping in Lotus’s at On Nut (right beside the BTS station) and decided to try out the food court. For 30 baht — 85¢— (I think it was) we got an absolutely scrumptious pork pad krapao. (FYI pad krapao — stir-fried pork or chicken with holy basil, rice and fried egg — is like a quick burger or sandwich for Thais on the go). There were plenty of curries, noodle soups and other classics on offer.