Prices have gone up in recent years, largely because of an influx of expats and tourists, and not everyone has been respectful of local rules or culture. That said, it remains an affordable place to live and travel with a very high quality of life. Each country has it's own flavor so....
I absolutely love Thailand. In the north, you’ll find beautiful nature, national parks, and animal sanctuaries. The south is famous for its stunning beaches and islands. Bangkok, located centrally, feels like a major global city, very well developed, with modern public transportation, high-rise buildings, and endless things to do. The food scene is incredible, ranging from Michelin star restaurants to food halls and unforgettable street food. One of the best parts of being based in Bangkok is how easy and affordable it is to take weekend trips to other countries in Southeast Asia. On average, a 3-star hotel plus food will cost around $80 per day, making it extremely budget friendly
Vietnam is quite similar to Thailand but generally cheaper, mainly because it’s less developed. While it’s not as Westernized, the food is absolutely top notch and in my opinion, even better than Thailand. Your money goes a long way, and although English isn’t widely spoken outside tourist areas, people are incredibly friendly and welcoming. Vietnam is rich in history and culture from north to south. Just keep in mind that a visa is required for entry.
As for Cambodia, I wouldn’t recommend staying too long. It’s very poor and underdeveloped, though U.S. dollars are widely accepted. A three to four-day stay is usually enough. Angkor Wat is a must-see, especially at sunrise and sunset, and is truly unforgettable.