make a fast buck

To make a fast buck means to make money with very little effort and in a very short amount of time. Any time a fast buck is mentioned, they are speaking about earning money very quickly, and usually without a lot of effort or hard work in order to do it. It is often spoken when someone has found a way to make money quickly to some type of scheme or a way to get a small amount of money quickly, which is often worded as making a quick buck.