should always be done with discretionary income that you can afford to lose. https://cirandas.net/freetto/blog/%EB%A1%9C%EB%98%90-%EB%B2%88%ED%98%B8-%EC%A1%B0%ED%95%A9-%EB%B6%84%EC%84%9D-%EC%A0%84%EB%9E%B5%EC%A0%81%EC%9D%B8-%EC%A0%91%EA%B7%BC%EC%9D%84-%ED%86%B5%ED%95%9C-%EB%8B%B9%EC%B2%A8-%ED%99%95%EB%A5%A0-%EB%86%92%EC%9D%B4%EA%B8%B0
