If you are in Klang Valley, there is a place in Subang New Village where they do Tilapia. They sell each fingerling at RM 0.25.
Tilapia is a cheap fish not many place want to keep stock since they eat and require same attention as that of more expensive fish.
Below is their location
Some of the RM 0.25 Tilapia Fingerling, these cost more but after taking consideration of how far you need to travel to get a cheaper ones, this is a better option.
GPS : N3.14498 E101.53768