@Lay ******
I am in a similar situation as you and I am currently living in PP. I was at the Thai embassy in PP at the end of the year to pick up the Non O application. The agent there was pretty distant when I asked him some Qs. However, he did say I would need to show a bank statement, but he wouldnt say how much. I pressume it would be
800,000bt equivalent. I also asked I would need to show a plane ticket out, hotel, etc. He walked away...I do believe the apication there is for a year, at 200$ app fee, not 3 months. You would need to leave every 90 days. This is one reason I.m not sure if I.ll apply. I also recall there is a space for your Cambodian address( along with your home country address)
If you want to PM me, we can have a follow up discussion later. I have the application form stored somewhere.