Tough for 2 to live on $3K, unless you can really live like a "typical" local. By that I mean
1) Use public transport (with bus/MRT as the first choice, not taxis!) as much as possible;
2) Buy from the neighbourhood NTUC instead of Jason's;
3) Eat at hawker centres instead of restaurants and cafes;
4) Rent a HDB room instead of a district 10 condo.
My starting pay was $2K and I had to support 2 people (mom and studying brother) and service a study loan. But the house is paid for and we don't have the "usual" luxuries at home (e.g. aircon, cable, computer) so it wasn't too tough. But I did have to forgo the though of buying new clothes for a while.... after 3 years I'm just starting to buy some new suits. I could still afford the occasional outing to restaurants (cheaper ones). You really need to tighten your belt and watch every cent.
Now I'm married but am still contributing to my mom's household allowance. But my pay has since risen and my loan paid-off, which is a great relief.
Well, one thing good abt low-pays: you pay less taxes to the government!