A capped retail dispenser package encloses and retains a mixing container into which a product mixture is filled using an automated manufacturing system in an individualized manner, such that each individual product container may be charged with a customized or unique formulation different than a previous or subsequent container passing through the system. Mixing is not done prior to filling, but with a mixer received in a slidable bottom portion that functions as a piston. The rod terminates at its upper end with a mixing plate. Movement of the rod through the central opening provides mixing of the product through a reciprocating motion, and preferably with a simultaneous rotation. Movement of the upper mixing plate within the mixing container provides mixing of the container's contents by forcing fluid flow through one or more mixing apertures formed about a flange of the mixing plate.