You mean - it's cheap BECAUSE it doesn't include batteries. And as it doesn't say it includes batteries, why did you expect it to?
People who return things because of their own inability to read a description, and whose expectations are unrealistic, put up the cost of things for everybody else.
Furthermore, if you buy batteries from the right place (not a supermarket or Boots) you will find that this item plus the cost of batteries still costs less than the more expensive one you mentioned.
I despair of some people.