http://list.qoo10.sg/item/SAMSUNG-ELECTRONICS-SAMSUNG-S27D590P-27INCH-LED-MONITOR/421925918Not possible to get 144 Hz refresh rate at 300 sgd locally. The cheapest of the cheapest monitor I can find on amazon at 144 Hz 1080p would be this: Asus VG248QE 24 Inch LED Lit with 1ms response time. But I would not really recommend this as it is using a TN panel with a very glossy screen (easy to see your own reflection). Warranty and shipping is an issue as well.
Like others said, I recommend the U2414H from Dell. IPS panel + matte screen. Response time of 8ms doesn't really affect gaming much as the human eye can't really differentiate between 1ms to 10ms (0.00x seconds, average human reaction time is 0.25 seconds. If you can make a decision in game in 1/100 seconds then go for 1ms, otherwise no diff).
Great monitor for gaming as well (I play competitive LoL and CS:GO with this monitor), without the distraction of your own reflection (unless you always play in a dark area).
However, of the games you mentioned, the only games you might benefit from with a 144 Hz monitor will be CS:GO (more fluid movements and the few frames can help you spot an enemy). The difference will only be significant if your rank in CS:GO is at least LE (Legendary Eagle).
If you are looking for a 1080p monitor, 23 to 24 inch will be the perfect size. Any bigger and you will notice a drop in quality. Only get above 25 inches if you are looking for a 2k monitor.
is this okay?