Thanks Scubadudee. 
I'm not that worried about accommodation and flight. It isn't my first time to Thailand. Did some backpacking there before. I'm going alone actually, so yes, sometimes I missed out on some good deals for pairs, be it flight tickets or etc.
Well, I heard it's compulsory to get the manuals now. Guess I can dropped by some of the diving shops to get it or simply do a course with the diving schools which comes with it. Was thinking of doing it in Phi Phi, cos everyone is encouraging travellers to contribute there, but the accommodation there ain't that cheap and there's a good risk of fully-booked rooms during Songkran. That is why I chose to go with Phuket if possible. I can always dropped by Phi Phi later after I got certified.
I am budget conscious (call me cheap if any of you want to), but I don't mind paying a bit more to get good diving and coaching. Saying that, it doesn't mean I'm willing to be easy with my money and neither do I want to be overcharged for the unnecessaries.
Well, still leaving my options open though and I welcome any information all you divers out there can give me. Thanks.

I'm not that worried about accommodation and flight. It isn't my first time to Thailand. Did some backpacking there before. I'm going alone actually, so yes, sometimes I missed out on some good deals for pairs, be it flight tickets or etc.
Well, I heard it's compulsory to get the manuals now. Guess I can dropped by some of the diving shops to get it or simply do a course with the diving schools which comes with it. Was thinking of doing it in Phi Phi, cos everyone is encouraging travellers to contribute there, but the accommodation there ain't that cheap and there's a good risk of fully-booked rooms during Songkran. That is why I chose to go with Phuket if possible. I can always dropped by Phi Phi later after I got certified.
I am budget conscious (call me cheap if any of you want to), but I don't mind paying a bit more to get good diving and coaching. Saying that, it doesn't mean I'm willing to be easy with my money and neither do I want to be overcharged for the unnecessaries.

Well, still leaving my options open though and I welcome any information all you divers out there can give me. Thanks.