there is no freelance board where everyone can refer to for rates.
perhaps it is just not as well regulated in Malaysia in comparison to other more developed countries like US/UK.

I've heard before that people use their ideal monthly salary, and divide it by days of work to get the daily rate. Then determine how many hours you would put in a day, you will get the hourly rate.

For example:
RM7000 (ideal salary as of now)
7000/22 = RM318 per day.

Working hours per day is 5 hours.
RM318/5 = RM63.6 per hour.

Please note that it is not accurate but at least you have a benchmark to refer to if you don't have ANY figure in mind on how the rates work. There is still some mark up to do for when the job well is dry.

Hope it helps.