You are coming from the USA so you need to deal with the Thai Consulate for your region. Go to the Thai Embassy website and find out what region you are in. After finding which one go to that Consulate website and learn the requirements. I have done it 3-time. Simple, easy, and quick if you follow the instructions and have no underlying issues.

Thank you for the feedback, but I am quite clear about what he said. What he didn't say is that he wanted to apply for a i-year extension. I generally don't assume what people have on their mind. My bigger point was if you can't afford the price of admission try another path.

I can't think of a good reason for a US Citizen needing a non-o visa for a 90-day visit. Come to Thailand without a visa and stay for 60-days. As you get near the end of 60-days apply for a 30-day extension. I have never seen an extension denied. My answer applies if you can't demonstrate the financial resources required.