Digital media is something that has really changed the way that the world works. It has created a large shift in the way that information is passed along and in the way that entertainment is found and purchased. Computers allow music to be shared in mere moments. They allow whole books to be transferred from a seller to a buyer without any physical transaction taking place; these books can then be read on the screen. There is this whole culture of instantaneous transfer of goods. It has progressed to the point where people do not even like to wait for any amount of time. They do not want to make a purchase in a store because that would mean leaving the house, driving to the store, and waiting in the check-out line. You can make use of this culture with your free sample marketing.
In short, you just need to give away small pieces of the whole. You cannot give away the entire thing, or people will have no reason to make a purchase. Bands will often release the first single from a new album free of charge, hoping that people will be so impressed that they will buy the entire album. Writers will sometimes release the first chapter of a new book, hoping to get people hooked so that they will buy the entire book.
In certain cases, you may be able to give away an entire product. An author, for example, could make the digital copy of one of his old books available for free on the internet. This would then spark interest in the author's entire body of work, which would help him to sell more copies of his upcoming book. Bands could use this tactic as well. It can especially be executed with older material that is no longer selling anyway. Since it is not bringing in revenue, it can be distributed for free without any sense of loss - seeing as how one digital copy can be given out many times and does not cost any more to produce - and it can help the revenue that is created by other works.