I would like to know my single entry visa finishes on the 6th october i took a trial run up to masai the immigration officer told me i can make an extension of up to one month at airport currently I am in chiangmai thailand can this be done at chiangmai immigration at the airport and someone told me the fee is only 1900 baht and do I have to do any visa runs up to masai burma as well

Hey its simple just go to the immigration close to the airport. As soon as you walk in the door there are form on you left to fill out for tourist visa extension I thing they are the T7 (marked like this in top righ corner of form) forms. Fill this in and then go back to the Thai gut near a ticket machine close to the door tell him "tourist visa extension" he'll produce a ticket for from the machine. take a seat wait for your number to be called and go to the appropriate window and hand him #1. your passport. #2. a photocopy of you visa and last stamp into the country and also your picture page. #3. the form you filled out on entering the immigration office. #4. a passport sized photo of your head and shoulders. #5. 1,900 baht and a pleasant smile. After this he will tell you "take seat" and then wait for your name to be called out over the tannoy or a loud mouth worker. Take care to listen for what might be your name as their pronunciation is not the best when it comes to farangs names.

Sorry and all you'll get from Mai Sai, when this extension will run out (because you say you only have a single entry visa) in basically 15/14 days visa on arrival. If you want to stay longer in Thailand, you are best off travelling to Laos and getting another touris visa from the Thai consulate in Vientianne.