What would be considered a waste of money ?
وعليكم السلام ورحمة الله وبركاته
Wasting money has many forms , which can be generally brought under two forms .
It is when the money is spent in things one does not need like how it is mentioned in the Hadith of Jabir bin Abdullah رضي الله عنه that the Messenger of Allaah صلى الله عليه وسلم said ( A mattress for the man , another for his family , and the third for his guest , and the fourth for the devil ) narrated by Muslim . So the forth one is for the devil because there is no need for him in that fourth one !
It is when you spend the money on something less important while there is something more important . For this reason , spending on children and close family members is obligatory and its reward is greater than the Mustahabb charity , and the best charity is what you give to those who are related to you because they are more important than others.