I posted this last month in the health & nutrition section, with not one person replying. Perhaps I can get some info from here. Surely somebody out there is familiar enough with it to answer. I am familiar with what probotics are and why they are needed, however, I am confused about one thing. When shopping for some, I find both contents & price cover a very wide spectrum. Some have only one main ingredient, others have a different one or have several. I've seen one months supply range in price from a little over $3. to over $40. What gives?