Your budgeting method is slightly flawed. Would you prefer a RM40 for a 20ml moisturizer or RM100 for a 80ml moisturizer? Packaging size is the most common tactic to make skincare look cheaper. Besides packaging, there are other factors to consider too but it’s a bit lengthy to explain.

If you're looking for exact product recommendations, I don't have any unfortunately    You gotta explore on your own regarding that.

I can give pointers to look out for only.

For sunscreen, SPF 30-50 is correct for normal day to day use.
For moisturizer, try to get gel or water based ones cause i think your skin is dehydrated.
Avoid toners with alcohol
If your skin is really dull, consider exfoliating (scrub) or get something (usually serums) with vitamin C. 

If you want easily accessible places, just visit Aeon Wellness, Guardian or Watson. If you're brave & adventurous, visit skincare shops like Sephora, Sasa, Shins, Body Shop, Face Shop etc.

Owh yea, there are some Malaysian vloggers that you can follow to learn more if you want.

- UV Perfect Face Milk
(This is waterproof so you might want to buy makeup remover to remove it, I use cleansing oil.
Also, this sunscreen does leave a white cast and may make your skin look ashy when applied if your skin is abit darker.
Lastly, this made my skin dry. If you have oily skin it's great for oil control)

Biore UV Body Serum Intensive White makes a great body sunscreen

For moisturizer I've always used Nivea Cream if I need heavy duty hydration. On my normal days, I use Nivea Care.