Last time I always thought that it's best to buy Infant Formula Milk during the promotion time of all the supermarkets (Aeon, Aeon Big, Tesco etc). My favorite was always Aeon Big (formerly known as Carrefour). The offer can be very good especially if you shop on 28th and pay by your Aeon Credit Card. Then in total you get 10% off the item! For the rest like Giant, Tesco and Aeon, it is quite rare to see they offer a very competent price for their infant formula milk.
If I could not really wait until 28th day of the month for the Aeon Big discount, I will usually buy the infant formula milk at Speedmart99. The price is not the cheapest but it is still very much cheaper than any other supermarkets or hypermarkets on normal days.
Well, that was past.
Nowadays, I found shops that offer the cheapest formula milk are those chinese traditional medicine shops! Surprising isn't it! For example for S26 Promise Gold Step 2, some of these shops can sell you at RM52 whereas if you buy at other places the price usually will be in the range of RM65 - RM 57. Imagine if you need to buy in bulk, how much you can save from there. Right!