You CANNOT play WoW with just Burning Crusade (BC). You still have to buy the original WoW.

You CAN play WoW with just the WoW installed but then you can only reach until lv60 (max is 70 at the moment) and you cannot play Draenei or Blood Elf races and you cannot go to the outlands.

I forgot how much did BC cost but it's something around RM100-300 region. You have a few options for payment:
1. Buy game card, price is around RM100 for 2 months
2. Use credit card and you can choose 3 types of packages.
a) USD14.99 for 1 month
b) USD13.99 per month for 3 months (have to pay for 3 months at the begining)
c) USD12.99 per month for 6 months (have to pay for 6 months at the begining)

No refund for any of the payment options.

You can try a 10-day free trial but you'll need a credit card for that. Also some people believe that if you use the 10-day free trial in Malaysia, your account might get banned but this is just speculation at the moment. Up to you if you want to take the risk or not. You can upgrade your account to a normal one and continue your character after the 10 day trial expires if you wish to.

Play Horde not Appliance (or they like to call themselves Alliance)!