Should change this thread to cheap and fast way to early death!
Veg is cheap at the wet markets
$8 for two large bundles of choi sum.
Enough to last you a few days.
Get yourself a rice cooker and start steaming veg etc, make congee and add some minced pork and egg and so on.
Cheap and easy and at least you know what's in it.
If you are not minded to cook for yourself (I understand; some of us don't have the time!) then get your fruit and veggies as snacks through the day. Buy some fruit and put on your desk/at home and eat between meals - both keeps you full and also gives you vitamins and fibre. You can also eat raw veggies at the same time - raw carrots are delicious. Also things like celery are easy to eat a stick now and again. You should also buy some nuts / sunflower seeds etc as snacks - also good and variety of nutrition.
Personally I love chicken and eat for most meals (not breakfast - yuck) so that's not a problem. Just add some of the fruit/veggies/nuts and you will be fine.
I'm a huge fan of Nood Food (I think all Pure locations have them, but I typically go to the location in Kinwick Centre on Hollywood). As an ex-New Yorker, it reminds me a lot of Dig Inn or Pump Energy Food (or Pumpernickles for ex-Canadians).
You can get an order of roasted white meat chicken (w gravy if you want to splurge) that comes with 2 or 4 side salads ($92 & $113 respectively) and the portions are very generous.
The salads are quite good, and they change them up fairly frequently, although I almost always go for the mainstay kale salad with avocado dressing and quinoa & beetroot salad.
I think the main problem the OP has is the combination of CHEAP and HEALTHY and NOT HOME COOKED.
That is certainly a challenge in HK.
i find this thread so confusing. when did congee or porridge become the heathy food? when i get off work late, i will just buy some vegetables (and green bean) and just cook some chicken. if i am not on a low carb diet, i will also bake some sweet potato. fruit is also a must. its not ridiculously cheap but at least its enjoyable and healthy.