back from Thailand. Got the Dtac happy tourist card at the airport dtac counter. they will help u change the sim, do the settings and test the phone before passing back to you. save the hassle plus most of their instruction and sms is in thai.
the broadband seem to be just 1gb and not unlimited as claims. like in sg, in the city, the speed slows to a snail pace at some locations. outside bkk is better speed.
once u reach 800mb data, they will send u sms to warn u. so yeah please take note not to send ur pics freely as if it is really unlimited..
thai to thai call is 1.5bht per min. thai to sg is 3bht per min. u get 100 bht worth of calls for 299 tourist happy sim.
my suggestion is to give AIS tourist sim 299 a try instead of getting dtac only.