Well, the only thing an agency does is to go to immigration with all the papers the client has to prepare himself anyway. And the preparing is the most ennoying and time intensive work.
Only the local immigration can give you the latest requirements because every province has its own requirements. This is the only and best advice that actually can be given
the same in other countries outside Europe. They all hold you trapped until you pay. Not only in Thailand or the Philippines. The main thing is, with travel insurance you get the money back you paid abroad.
lucky you if you didn‘t need it never had an accident or got sick. I‘m glad I had one on my travels across the world the last 40 years and several incidents.
you cannot stay in Thailand then for more than 60 days like a tourist. Either apply for tourist visa 60 days and extend it at immigration or with a 30 day visa exempt and extend it 30 days.