Thailand Hotels and Hostels

Thailand is the land of backpackers, but it's also filled with resorts and high end accommodations for people looking to escape it all. Thailand is easily the most touristy country in Southeast Asia and it's easy to see why. The beautifully blue beaches are the main draw. For this reason you'll find hotels and hostels are far more expensive in the south than they are in the north. Even so, it's still Southeast Asia, and costs remain quite low.
The diversity of the Thai landscape means that you will likely want to visit more than just the beaches. If you choose to take a trek you may find yourself staying in some rustic accommodations in the jungle. These prices are typically built into any package that you book. Confirm ahead of time so that you understand what is included in the price and what is not.

Finding the Best Prices

It is possible to get some incredible deals on accommodations in Thailand. If you're a scuba diver, you can usually get some hefty discounts if you book your accommodations through your dive company. If you're getting certified, it's possible to even get free accommodation.
Similarly in Chiang Mai, if you plan to do a multiday trek you can likely get your accommodations free at the guesthouse you go through. If you're not doing a trek, it can even be a little tricky to find accommodation at all, as many of the guesthouses, reserve rooms for the travelers who book treks.
It's possible in many places to show up without reservations and negotiate a good deal, but in some of the popular beach resort towns, you might find accommodations full by the time you arrive. Do a little research and plan ahead. Even if you make reservations ahead of time though, remember to negotiate the price. Everything in Thailand is negotiable.
If you plan to stay in an area for a lengthy amount of time, ask if you can get a discount. Sometimes you can negotiate the price down based on the length of time you plan on staying.

Types of Accommodation

Accommodation in Thailand can range from the most luxurious resort catering to the rich and famous to the most rundown shack that sits on a sandy beach. If you're a budget traveler, you'll find that most of the cheapest accommodations are in the north, while hostels in the southern beach areas are far more expensive and of a much lower quality. Don't be surprised to find yourself in a half collapsed wooden shelter packed amid rows of similar quality. If you want better accommodation, you're going to have to pay more for it, and even then, the quality likely won't be what you find in the north.
In Bangkok you'll find most of the budget accommodation in the Koh San Road area. This is the area that caters to backpackers and partiers and there are countless bars and clubs as well as street foods. If you're looking to get a better feel for the city itself, you may want to look outside of this neighborhood for accommodation. It is possible to find cheap guesthouses in the other areas in the city that have a more authentic feel such that you can escape the tourist crowds.