The wedding preparations start with the sou khor (bride-price negotiation) procession.
The bride-price is usually money and gold, but it can be anything valuable. Traditionally this is asked by the bride's parents as a refund for the breast milk that has been fed to the bride since she was born (literally translated from Lao). How much? depends on the family social status of both sides. Nowadays many parents don't ask for anything so long that their daughter is happy.