Let me give you a tip on how to save on hotels in Thailand. Go to Wotif.com and search for hotels on your dates. Look for the 'Wot Hotel mystery deals'. These are hotels you book without knowing what you get besides the star rating. It's used by hotels to fill rooms without seeming cheap and empty to the general public.
So for example, I choose the 5 star hotel with the price of 2707 baht and I find the description of the hotel:
"Is ideally located in the heart of busting shopping malls and street bazaars. Featuring spacious rooms and suites, sumptuos restaurants and excellent leisure facilities including the tranquil Breeze Spa."
I then copy this and
Google this string.
The first result is from
this site where I can read that others have identified it as being the Amari Watergate Hotel. At Agoda.com the current rate for the same date is 3300 baht and so I've saved 500 baht pr. night booking through Wotif and googling to find out what hotel is behind the 'mystery deal'.
It's by far the cheapest way to book 4 and 5 star hotels and some 3 stars.