Dies ist ein sehr weit greifendes Thema. Um eine einigermassen akkurate Beschreibung der Traditionen und Abläufe geben zu können, müsste man etwas genaueres Wissen über die genaue Herkunft der Frau. Das ganze Prozedere wird von Dorf zu Dorf zum Teil unterschiedlich vollzogen. Genauso wie die Sprachen im Isaan (Thai, Lao, Kamboscha, Guy etc.) unterscheiden sich teilweise auch die Bräuche.
Im generellen sieht der Brauch allerdings vor, wie bereits gesagt in diesem Treat, dass das Aushandeln des Brautpreises und die Festsetzung des Hochzeit-Termines die Verlobung darstellt. In meinem Falle geschah dies im kleinen Rahmen mit dem Vater der Braut, dem Dorfältesten und ca. 2 Flaschen Mekong. Wobei der Termin nachträglich noch von einem Mönch also OK abgesegnet werden musste. Aus irgend einem Grunde wurde bei diesem Anlass aber nicht über Geld gesprochen, obwohl ich es erwartet hätte. Die Festsetzung des Brautpreises wurde mir überlassen. Auch später war mir meine Frau keine grosse Hilfe bei diesem Thema. Sie hat trotz nachfragen nie eine Zahl geäussert.
In einem anderen Forum habe ich vor einiger Zeit meine Hochzeit beschrieben, allerdings auf Englisch. Ich kopiere dies nun im Original hier rein und hoffe dies ist erlaubt (es handelt sich dabei ebenfalls um eine Antwort auf eine Frage).
dsap,
To answer your question. I get married in Isaan over a decade ago. Here my experiences and explanations I get at the time for the whole procedure.
1) After discussing about it, my father in law fixed the date of marriage together with the head monk from the Wat nearby. The dates they figure out shall grant that our marriage is born under a good star and shall be happily for the rest of our lives.
2) An odd number of monks were invited to handle the marriage (at least 5).
3) The marriage took place at the home of my wife. She was supposed to arrive at home at least one night before the marriage took place.
4) I arrived one day later together with my family. We were told to bring gifts with us for the monks. Right after arrival we had to give over these presents.
5) Me and my father were asked to sit down together with the head of the village, my father in law and my fiance by the time. And I handed it over to the head of the village.
Conc. the dowry: I was told prior to marriage that it is totally up to me what I am going to give. I handed over 50'000 Bath. As I could figure it, this was OK. At least nobody shouted something like Cheap Charly when the head of the village was counting it over the microphone. BTW, two years later my sister in law married a Thai guy (this still happens) he handed over 10'000 Bath. So I figure my 50k were fair enough.
Is 300'000 Bath too much? No idea, this is up to you. But I would figure that a Thai would not ask for the same amount if you would be Thai.
To the meaning of this money, I was explained that normally the head of the village is handing it over to the father in law (this happened so far). Later on the mother in law will give it back to her daughter. The meaning is that she shall use this money to build up an own household. Of course, the second part will most probably not happen to a farang. Even though my wife asked me if I like to get the money back. BUT, excuse me!!!
6) Important: Bring 5 Bath of gold with you in any form (necklace etc. etc.). You are asked to hand this over directly to your fiancé. Again, the head of the village will carefully check if it is 5 Bath (more is no problem) and announce the weight to the guests. I figured the gold was almost more important then the money (even this is certainly not true for the family, as they could keep it). Ask your GF about this.
7) Now the ceremony starts. I spend nearly 4 hours on my knees going through the whole procedure. Jesus, my knees!!! Get trained

.
8) The big drinking starts.
Believe me to marry in Thailand is an experience you never will forget (a good one BTW). And also your family in law will not forget it as you showed them respect and interest in their culture (doesnt matter what your going to pay).
The above was my marriage. A second one I attended went on exactly the same. But however, this does not mean that it is everywhere in Thailand the same.
Sanuk