1) Deep pockets
Don't face that evil company in court, they have deep pockets
Clara married Henry because he had deep pockets
Anyone who buys that TV station will need deep pockets, since they are bankrupt
Definition: they have lots of money
Etymology: The term "deep pockets" (also given as "deep pocket" and "deep pocketed") is attested sparsely in the 1940s through the 1960s, but became popular with the litigation explosion of the 1970s.
2) Easy on the eye
Amber may be easy on the eye but she is totally conceited
The out-of-work auto-show models are easy on the eyes
The painting is both easy on the eyes and thought provoking
Definition: pleasant to look at
3) Fight fire with fire
Sometimes you can fight fire with fire in diseases, like getting cowpox to get an immunity to small pox.
The government fought fire with fire, by employing black ants to kill invasive red ants
In World War 2, the Nazis attempted to fight fire with fire and hire snipers to shoot the master Soviet sniper
Definition: you use the same methods or weapons as your opponent
Etymology: Although ancient writers from Plato to Erasmus cautioned that one should not add fire to fire, this warning is not incorporated in the idiom, which was first recorded in Shakespeare's Coriolanus.