a agent will charge about 35,000 baht and they do everything for you that's what i paid im sure there are cheaper if a marriage visa get it done in Buriram you have to show 400,000baht in a Thai bank account there is no Spouses visa retirement visa you have to have 800,000 baht in Account for 2 months to be granted visa i applied in Thailand no problem a agent will open a bank account for you but you must apply in the province you are going to live in