Rubber Duck
Godzilla
Acquiring a Godzilla presents insurmountable financial challenges. No legitimate market exists for purchasing kaiju, and the theoretical costs of creation would exceed most national GDPs. The creature's dietary requirements - presumably substantial given its mass - remain undocumented but certainly astronomical.
Indirect costs prove equally prohibitive. Property damage from a single Godzilla appearance typically runs into the hundreds of billions. Insurance premiums in Godzilla-prone regions reflect this reality. The monster is, by any reasonable accounting standard, economically catastrophic to possess or even encounter.