We can't stop spending money on wars because there is still a major terror threat to this country. We can't just sit with our hands behind our back and do nothing about it. I do think we need to be careful with our spending and know where it's going, but it's currently necessary to spend money on wars.
Obviously the US might be put in a situation where we have to go to war, like a direct attack. Otherwise, it is time for America to take a step back and take care of the problems we have at home. We have a dying infrastructure and veterans we already aren't taking proper care of. We need that money for those things.
Wars never really accomplish anything, and unlike during WWII or in the book 1984 they no longer help to boost the economy. It is better to stop spending money on wars and find other ways to spend money, like education and aid for the poor. Throwing it down a toilet would be better.
As a country, we've wasted so much money on ambiguous foreign conflicts (technically not wars, because congress has to declare war) since 9/11 it's clear that we've played right into the hands of Osama Bin Laden. We keep spending massive amounts of money chasing people halfway across the globe that have no realistic chance to harm us. We've got to stop it before it completely bankrupts us.