This is just a quick post aimed at those using mobile phones in Thailand. Unless you are fluent in Thai script it is difficult to understand the many different payment packages that are available, and talking to the sales people is a bit like banging your head against a brick wall.
Anyway when I was last at Bangkok airport, True had a time based package information pamphlet available. I thought the following information may be useful to smartphone users who use the True network in Thailand.
In all cases text the message to 9789, and wait a few minutes for the reply before using the service.
39 Baht (EDGE/GPRS) send text message: D1 (period midnight to midnight)
49 Baht (EDGE/GPRS 3Hrs Wifi) send text message: D2 (period midnight to midnight)
Monthly packages by the hour (choose one per 30 day period)
20 baht (EDGE/GPRS/Wifi) 1 Hour; Send text message: H1
30 baht (EDGE/GPRS/Wifi) 2 Hours; Send text message: H2
50 baht (EDGE/GPRS/Wifi) 5 Hours; Send text message: H3
99 baht (EDGE/GPRS/Wifi) 20 Hours (3G) 5 Hours; Send text message: T1; to cancel CT1
199 baht (EDGE/GPRS/Wifi) 50 Hours (3G) 10 Hours; Send text message: T2; to cancel CT2
349 baht (EDGE/GPRS/Wifi) 100 hours (3G) 15 Hours; Send text message: T3; to cancel CT3
Monthly packages by Volume (choose one per 30 day period)
129 baht (3G/Edge/GPRS) 100 Mb + 5 Hrs Wifi; Send text message: V1; to cancel CV1
399 baht (3G/Edge/GPRS) 500 Mb + 10 Hrs Wifi; Send text message: V2; to cancel CTV2
699 baht (3G/Edge/GPRS) 1 Gb + Unlimited Hrs Wifi; Send text message: V3; to cancel CV3
For the monthly plans you can check your balance by sending text message: B to 9789
If you do not use a package the charge is 1 baht per minute.
Hope that this information is useful to you,