I recommend this one at Mountbatten. Make sure you go. Its really $2.50 for a bowl of fishball noodles. Its at
Old Kallang Estate Hawker and Wet Market. Sibei solid chili and distinctively their own taste. You wouldn't regret it. I eat there at least once a week, so maybe I will bump into you Lol
They open very early (as early as 5am). So do the other stalls at this hawker centre. Sometimes, if I have an early flight, I drop by for breakfast before continuing my journey to changi airport.
PS: It's
not that well known Old Airport Food Centre. It's the one with the wet market which is before NTUC if you are heading from city to airport.