used to refer to something painful/dangerous/regrettable/otherwise negative associated with doing something you have voluntarily chosen to do and therefore implicitly accept the possible risk of.
>John: "Sorry if that round of tequila shots I ordered at the end of the night pushed you over the edge."
>Humberto: "Haha, no biggie. Cost of doing business with you man."

In this case, "doing business" refers to hanging out with John. the "cost" is the risk of getting too drunk because John likes to order tequila shots. Humberto is saying that by voluntarily hanging out with John last night, he implicitly accepted the risk of having a tequila shot served to him that may not have been a good idea but that he, in his intoxicated state, may consume anyways.
by reezydos July 13, 2014
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