if you are on a non-o M you dont need to bring anything besides your passport. i dont know how it is if you do it at a cambo/laos border but mae sai border for myanmar there is a 500 baht fee as well.
Yes I know that Sorry if my wording was off. During the course of the extension of one year during 90 day check inns well I need to continue to prove income or no? Is that just a one time deal when you apply for it?
On top of the income affidavit, will I need to show any other proof of funds at the immigration office? I have a work permit here as well from an after school english center that I teach at. I have income from USA and thailand.