to (one's) cost
to (one's) cost
To one's detriment; due to one's personal experience with something negative. Unfortunately, he's not as forgiving as we all had thought, as I found out to my cost.
See also: cost
to your ˈcost
(know, discover, etc. something) because of something unpleasant that has happened to you: Joanne’s not a very reliable person, as I’ve recently discovered to my cost.See also: cost