At 1st my dad ask how much my future MIL want, then MIL said " we make decision " (so call cincai )

Yes, tat is the thing that pulling everyone's leg.. but you guys can still decide not to marry them. Decision is still in your hand.
Is good if the gf standby you to fight off or nego the dowry part.. if she is those kind who sided her parents more than future husband, so either leave her or take it. Is still the man's call.

Raising a son is free?

well, i think just told her, i dont really afford to pay 10k... maximum i can do its 5k... hope that my MIL understand..

She said something about 'if you want to marry me, this is necessary'.

Actually the contract is a recycled one, written by her grandad for her elder sister who got married 2years earlier.

Im jus thankful there is no inflation in prices

Not sure bout you all...but she does want kids (me not really lah, kids expensive lah).

Actually when sign the contract we go have dinner in a restaurant, got bring witnesses, grandparents n parents (both sides) n sign in front of them.
haha. first time i hear of this (actually first time is when her sister husband or my bro in law sign first).