RM500+ for boracay return is the cheapest?

correct
i compared the price when buying ticket and the difference is RM9 and above

first time booking flight?

you have to see the keyword FROM and ONE WAY
also, it only limited to few seats(not all). once the seats taken, the price will back to higher
the fare is only for ticket without taxes.

quick question
can i bring 2 or 3 luggages for a single 20kg baggage allowance?

cool.
am planning go include 3 cabin luggages into check in baggage

not sure about luggage but 2nd question, yes

From website:

Self-transfer during stop

You'll need to transfer flights by yourself on this leg of your trip. The airline doesn't provide the transfer. Therefore, you may need to:

Clear customs and immigration
Check in for your next flight
Recheck your baggage