I'm coming to the end of my job, but I want to tour around a little before I go. My work visa runs out on September 30. How do I get a tourist visa for a few weeks after that?

If you are on a 90 day visa entry that expires 30 September and wish to obtain a tourist visa entry leave to Vientiane or other Embassy/Consulate and apply. Will require an overnight stay but visa will be free.

If you are here on an extension of stay from Immigration that will end the day your work ends and you can leave then or extend 7 days. You can obtain a tourist visa entry as above.

If you are on a 90 day visa entry that expires 30 September and wish to obtain a tourist visa entry leave to Vientiane or other Embassy/Consulate and apply. Will require an overnight stay but visa will be free.

If you are here on an extension of stay from Immigration that will end the day your work ends and you can leave then or extend 7 days. You can obtain a tourist visa entry as above.

I'm sorry, I don't understand the first sentence. What is Vientiane? Do I need to leave the country and come back? Is that what you mean? Can I go to my country's embassy and renew my visa? Right now I am on a non-immigrant visa.

Are you on extension of stay (Have a one year stamp from immigrations) then you have to leave the same day or get 7 days extension for 1900 baht from immigrations.

If you got your last stamp (until 30 September) at the border you can stay until that.

Tourist visas can only be obtained abroad at a Thai consulate.

Vientiane is the capital city of Laos.

Are you on extension of stay (Have a one year stamp from immigrations) then you have to leave the same day or get 7 days extension for 1900 baht from immigrations.

If you got your last stamp (until 30 September) at the border you can stay until that.

Tourist visas can only be obtained abroad at a Thai consulate.

Vientiane is the capital city of Laos.

No, I'm on my original 3 month non immigration visa.

Vientienne is the capital of Laos. Visit the Thai Consulate there and apply for a Tourist Visa.

Or any other Thai Consulate in a neighbouring Country.

You are fine until 30 September - if you wish to stay longer exit Thailand and for 15 days obtain a land visa exempt if eligable; or 30 days for air return visa exempt; or obtain a tourist visa from Thai Consulate in another country and return for that permitted to stay period.

You can never obtain a visa from your home country Embassy - only an Embassy/Consulate of Thailand can provide a visa for Thailand. So that would involve leaving the country.