if you google exantediet you will get all the info you need.., briefly it's a "Very Low Calorie Diet" 600 Kcals a day loads of water and various amounts of food depending on your weight loss aim (in my case no food - called sole source) !
Depending upon your weight loss goals you will be on working solution or total solution, total being total food replacement. You need to bring at least 3lts of water a day and exercise about 20mins a day to get the full effect of it. x
100 a month if you buy a bumper pack which will give you 1 soup a day, 1 shake a day and 1 bar a day.
If you don't like one of the soups you'll need to buy differently, such as a pack of shakes and bars which will work out about 150 pound for the month and you'll have some shakes left over at the end of it.