My tourist visa expires on the 27th & I leave on the 2nd of the next month.  The fine is 500 baht per day, and I can pay it at the airport when i leave.  is that correct?  Geting pretty nervous about this. Thanks

Yes you can.

 

When the IO at passport control sees you’ve overstayed they will send you to the overstay desk where you pay the fine and get your passport stamped.

 

Its a very common process and nothing to worry about.

 

You would be better advised to extend your stay (if you can) rather than overstay.

Note as well even if you have already extended you can apply for a second extension on your last or second last day. It will be rejected but they will give you seven days more (from the date of application, not your current stamp) to get out. This is cheaper (1,900) than six days overstay (3,000) as well as less legal risk.

It not likely to happen there is alway the risk of getting caught with an overstay on the way to the airport. 

IMO my it would be best to apply for an extension, pay the 1900 baht fee and be granted 7 days to leave the country after the application is denied.

Yes, no matter how some people may want to make it seem like a trivial matter, once your permission to stay ends you are in the country illegally.

 

You probably won't encounter a problem, but it's still better to be safe by getting an extension of your permission to stay at an immigration office or, if you already have one extension, apply for a second extension ... it will be denied but you'll still get an additional 7 days to leave.

Much better to get the extension at Immigration as you risk getting caught on overstay . This can easily happen should you be involved in any type of incident that involves showing your passport , including accident, pickpocket, assault etc . 

FYI he is going to get the 7 days to leave the country according to a message I got from him. He did not know that was possible,