try to buy the brand FAN (shanzi) 透明皂 in singaporethe soap is from china too, but for many years, i only found it at dayou supermarket at chinatown, next to chinatown market there, level 2. abt < $1 each, very good if u want to hand wash the underwear,etc.
next time if u passby there, take a look.
hoho, just found this soap in seng siong supermarket, $1.2 for 2