At the beginning, Quark sells Odo the baby changeling, getting a distracted Odo to put his thumbprint on the bill of sale. Initially, it looks like Quark is being a stereotypical greedy Ferengi. But then you look at the prices Quark quotes: five slips of latinum for a dead Changeling, ten slips for a live one, and eight slips for a sick one. If you recall from "Body Parts", slips are the lowest denomination of latinum: 100 slips to a strip, 20 strips to a bar. In effect, Quark was selling the Changeling for mere pennies. Moreover, if Odo wasn't interested, Quark intended to approach the Founders, not even thinking about approaching Starfleet Command, let alone the other Alpha Quadrant powers (who would easily have paid bars of latinum for their own Changeling specimen). In other words, while demanding nominal payment in order to soothe his twisted Ferengi conscience, Quark prioritized placing the Changeling in a good home over profit.
