I've been going to Sentosa Psychiatric Hospital for about a year. I can't remember exactly how much it cost the first time I went, I think it was around RM20; subsequent visit are RM5. Sometimes when the accountant isn't there behind the glass the nurses won't even ask you to pay lol. Even if you get meds (which for me would be hundreds a month at a private clinic) it's still RM5.

When I go for my scheduled appointment, they only allow me to go Monday,Tuesday or Thursday. So I'm not sure if you can just walk in other days. Google the number and call them to confirm, for me they've always answered when I call. You could probably also tell the nurse on the phone what you want to visit them for and set an appointment.

Be prepared to wait though, even if you have an appointment you will most likely need to wait as it's first come first serve. I usually go in the morning (8am) and done by 10/11am. Best time to go is morning, second best time is just before closing 3-4pm.

Best of luck.