Which visa r u after.I did it myself.If it's a retirement visa apply for non o in your own country.This gives you 90 days.With non o you can open a Thai bank account.Deposit 800k in account after 2 months go to immigration and apply for extension for 1 year.This is assuming you're after retirement.
You will need a letter from bank confirming your account and an update statement on the day you go to immigration.It sounds a bit complicated but it's not really.Just answer the questions on the form.If I can do it ,anyone can.
*****
baht is way to much.