Phuket is an island in the south of Thailand, comprising a number of beach and resort areas. It’s now almost as popular as Bangkok for foreign visitors, after rebounding fully after the 2004 tsunami devastation along some beaches.
Taken as a whole, Phuket is also the most expensive part of Thailand for visitors. There are definitely some affordable options, especially for those who are willing to stay a bit inland, but the deluxe resorts in Phuket are definitely expensive compared to anywhere else in Southeast Asia. The high season is from December through March, and there are so many resorts that competition keeps prices reasonable, but the rest of the year Phuket has the cheapest 5-star resorts in the world.
Once you have a room it’s possible to enjoy yourself and not spend much more, as budget food and drink options are available not far from most hotels, but if you want to snorkel or scuba dive or sail, it’s going to cost you.