My Thai friend who had an accident did no pay anything to government hospital. If he or she had Thai ID he might pay minimal fees. Different story if you are a foreigner.
Not by much but the prices of food and some groceries and basic necessities are less expensive here in Thailand. Also, the income of most people here are higher than in the Philippines.
You need to apply for work usually as English teacher. Then the school will provide the supporting documents so you can get a non B 90 days visa from Thai consulate in Vientiane Laos. Then you apply for work permit in Ministry of Labor. I don't think an agent can do that for you.