We had a short thread about this recently here.
You might want to check that thread, particuarly the quote from Oprah's magazine. Basically, the diet was very expensive because they require that you buy their own line of expensive and questionable supplements and even want you to buy their soap.
A lot of diet plans recommend short lengths of exercise, so if that is a priority for you, you could choose a better program. Jorge Cruise's 8 Minutes in the Morning has been popular and it requires a sensible diet, some exercise, and you don't have to buy anything extra. However, doing 8 - 12 minutes of exercise a day is only going to be beneficial if you do zero exercise right now. Once your body gets used to the few minutes worth, you'll have to increase it to continue getting any benefit. Though by that point, your body will be craving more and you won't mind, and hopefully your schedule will adapt as well. A lot of people need about an hour a day to lose weight.