I read "The World's Cheapest Destinations" while I was traveling around the world for eight months. In total, I visited over 25 countries, many of which are reviewed by the author in this book. I was able to test whether or not his recommendations were accurate.
This is a great guide to buy before you go on a trip, and you're contemplating where to go on a budget. It's a quick read and as complete as it can be, and only covers destinations that the author has personally visited.
Although the prices may not be 100% accurate, as long as you don't rely on dollar amounts, you will find the recommendations in this book particularly useful on deciding which places to visit.
Funny thing, the author said that there was only one country he would never go back to, and it's the Philippines. I found this tip particularly offensive when I first arrived in the Philippines and had a generally good impression of the country. However, after three weeks visiting the islands, I couldn't agree more! (Although truth be told, I would go back to specific islands for scuba diving only).
It's impossible to keep track of different prices around the world accurately in a book, no matter how many editions are printed. Many countries experience inflation in the teen numbers, therefore most likely prices will be different by the time you get there. However, relative to other countries, you will find that the 25 countries listed in this book are a good starting point for destinations to visit on the cheap.