someone calls your thai phone number while you are in usa. ur phone rings. u pick up. do u pay anything for this or is it all deducted from the caller? thx

Yes and it is expensive. I have AIS sim and pay 70 baht per minute when someone calls me in the usa. the caller pays the same rate no matter where you are when they call you meaning no extra cost to them. most thai carriers charge the same rates for intenatinal roaming such as DTAC and true.

I did get on a plan before the last time i went to the usa so now i pay now about 30 baht per minute when roaming there now.

retuning a call with an sms is cheap though and that is what i do when it is not important.

Answering or making a phone call on your Thai SIM while Roaming outside Thailand is Very Very Expensive.

Do not do it. You are charged, but the caller is only charged the usualnormal Thai rate to that SIM card.

You can receive SMS messages for Free.

Returning a SMS is as expensive or more than the per minute charges for making or answering a call while Roaming.

Yes and it is expensive. I have AIS sim and pay 70 baht per minute when someone calls me in the usa. the caller pays the same rate no matter where you are when they call you meaning no extra cost to them. most thai carriers charge the same rates for intenatinal roaming such as DTAC and true.

I did get on a plan before the last time i went to the usa so now i pay now about 30 baht per minute when roaming there now.

retuning a call with an sms is cheap though and that is what i do when it is not important.

correct!!!!

and costly

This is all correct and not different from any other SIM-Card used outside its home country...