YSK that if you're buying an over-the-counter brand name drug in the United States there is often a much cheaper generic alternative that is exactly the same but often much cheaper.
from /r/YouShouldKnow
YSK，如果你在美国购买非处方品牌药，往往有一个便宜得多的仿制药替代品，完全相同，但往往便宜得多。