Food in Phuket is quite more expensive when compared to the rest of the country. The reason for that is the touristy charm of this island that attracts loads of travelers.
A complete local Thai lunch at a decent restaurant starts at 150 baht, while western meals will start at a higher rate of 350 baht. Should you decide to add drink in the equation, you should expect to pay somewhere between 250-300 baht more. A good fish meal or a wine bottle will cost you around 650 baht. Everything that I have described above, expect to pay up to 25% more when in more touristy areas of the already touristy island.
A beer costs about 60 baht generally, groceries and basic staples for a week’s time will cost you around 1,000 baht. A better option would be that you eat from the street stalls, the food is absolutely delicious and surprisingly cheap. And instead of buying beers from the bars, buy them from a 7-Eleven store, it will save almost half of the money on one bottle.