If I purchased all of my dry goods at the LFS I would have been out of this hobby 20 yrs ago. Buy online, in large bulk containers = $$$ savings over the long haul. Many online vendors offer free shipping if the purchase is large enough. Amazon carries most/all of NLS formulas, so maybe start there.
As far as some of the newer NLS formulas, they cost more because they cost the manufacturer more to make. This goes for the probiotic series, as well as the newer formulas where Naturox is being used as a preservative.