As a tourist, staying in Hotels and Resorts, I spent almost $1,000US a week. After figuring out the secrets of Living on a Local's Budget in Thailand, I am currently spending around $600US a MONTH and that includes my expensive CrossFit Gym membership. It was slightly more when I was at a Muay Thai Camp full time but even then, with all of that included, I was spending way less than rent alone back in the states. If you want to live comfortably in Thailand, $1,000 will get you started.
For less than $2,000 US a month, you can truly live like a king.
If I had a $2,000 US Budget in Thailand I would rent a nice 1 bedroom Condo with a full kitchen, weekly maid service, flat screen TV, and a roof top pool. Average cost would be 15,000 baht - 20,000 baht a month which is around $667US. After paying for Wi-Fi, Electricity and Water, the monthly rent would be around $800US, giving me $1,200US to spend. If I ate at the nicest Thai and Western restaurants every day for lunch and dinner it would cost me around 13,500 baht ($450US) a month which is still super cheap compared to average restaurants back in the U.S.
Honestly I wouldn't even know how to spend $2,000 US a month in a place such as Chiang Mai in Thailand, I would literally have to go out 3-4 nights and week and buy rounds of drinks for everyone while living in the nicest place in the city. You could get a massage every single day at a night Spa or Resort for 9,000 baht a month ($300US) If you have the money, go ahead and rent the nice apartment, but use that extra money for savings and weekend trips down to the islands or even to places like Bali for your visa runs.
Examples include one month on the beautiful islands of Koh Tao, and Phuket and one month in the city of Chiang Mai. Monthly expenses including rent, food, utilities, internet, beer, and entertainment ranged from $600 - $1,000US per month and often included activities such as Scuba Diving, Massages, Muay Thai and CrossFit.