Hotels and guesthouses can be found in all corners of the country, even in many small towns. In general, the quality of rooms in Thailand are pretty high given the cost. Thais are a very clean people, and bathrooms are usually scrubbed and sheets washed before a new client enters, even in cheap places.
Prices for rooms depend as much on location as anything. Expect to pay at least twice as much in a tourist hotspot as you would in a small town off the tourist trail. The islands and Bangkok are certainly the most expensive. In a tourist location, the cheapest rooms go for around 250-350 Baht (US$8-10). In areas with fewer tourists, a traveler can usually find decent rooms with shared bathroom for B100-150 (US$3.50- $5). Extras like air conditioning or TV cost more. Dormitories are virtually non-existent.
In the countryside, homestays can be arranged for US$200-$250 a month including meals and accommodation. For expats renting a home, prices are reasonable. A studio apartment in a smaller city can be had for under $200 a month. For those inclined to live in podunk, a bush shelter is free and a wooden bungalow on the beach can be had for $150 or less during the high season, much less during the rainy season.
Camping on the beach is a real possibility in less populated areas, though most of Thailand’s beaches are now developed. Hobos will find it easy and safe to sleep rough in towns and villages, though larger cities should be avoided. There are parks in most Thai towns where a vagabond can pitch a tent or lie down on a cardboard mattress for the night. You’re unlikely to get attacked in Thailand.