Wiktionary
cost a pretty penny
vb. (context idiomatic English) To be expensive.
Usage examples of "cost a pretty penny".
The work was obviously done in Toolay, so it must have cost a pretty penny indeed.
We ended up with a hundred and twenty-five, who would promise to give us all their faeces, properly contained in the special receptacles we provided (and they cost a pretty penny, let me tell you), as fresh as possible, and over considerable lengths of time, because you want serial inspection if you are going to get anywhere.
It had all cost a pretty penny, Agar was certain of that, and it meant the pogue was well worth having.