A finder's fee was a concept in Ferengi business, a bonus for the person who identified a business opportunity. Ten bars of latinum on a fifty bar profit was considered an overly generous finder's fee.
In 2374, Grand Nagus Zek offered fifty bars of latinum as a reward for the safe return of an abducted Ishka. When Quark told Rom he planned to split the reward 30-20, with Rom getting the smaller amount, Rom protested the uneven split. Quark assured him that minus the finder's fee he would be getting, (having informed Rom of the reward) the split was even. (DS9: "The Magnificent Ferengi")