I know you guys are referring to Thai her but thought I would throw in my two bob's in about about Bali.
We are a family of four and excluding airfares and accommodation I budget on $100AUS a day for a two week stay. Some days we only spend a fraction of that, proved to my wife I could eat and drink (no grog) for less than 2 bucks AUS a day.
But then on the day we pay the tailor we probably spend 4 times our daily average.
For a long stay in Bali ie two months the daily budget drops about $70AUS a day.