The invention provides a method and system capable of allowing users to complete collections of objects without unwanted duplication thereof. The system automatically, and in response to user direction, determines if objects are available that would complete a user's collection. The system can automatically purchase and obtain delivery of objects identified as being needed to complete a collection. The system allows a user to statically define and derive the parameters of a desired collection of objects and can create, and suggest to the user, collections of which the user already has a portion. The system includes functionality that provides user-definable collections.