Lasting Power of Attorney is a kind of legal document that can be established by signing and provides authority for a person to act on behalf of another. In simple terms, it is a document that is used to enable one person to make decisions for another who may not be able to do so because of various reasons. For example, a child may not be capable of deciding on his or her own. And that is why a parent would seek the help of another to do so. Another person who may not be capable of deciding for him or herself might need a lawyer to help her with that. In both instances, the Lasting Power of Attorney cost would be dependent on whom you wish to use as a lawyer and how much your attorney charges per hour.