Go to the expense of something/of doing something - Idioms by The Free Dictionary
go to the expense of something/of doing something
go to the expense of (something)
To pay for something. I don't think you should go to the expense of renting a hot air balloon when your girlfriend has said she just wants a quiet Valentine's Day at home.
go to the expense of something/of doing something,
go to a lot of, etc. exˈpense spend money on something: They went to all the expense of redecorating the house and then they moved.