line one’s own pocket

line (one's) (own) pocket(s)

To make a large amount of money for oneself in a way that is considered greedy or dishonest. The phrase typically implies that one is prioritizing making money above some other, more admirable goal. He doesn't care about creating some digital utopia—he's just trying to line his own pockets. This new contract is going to line our pockets for years.
See also: line
Farlex Dictionary of Idioms.

line one’s own pocket

verb
See line one’s own pockets
See also: line, own, pocket
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • line (one's) (own) pocket(s)
  • line one’s own pockets
  • line one's pockets
  • line own pocket
  • line pockets
  • line your /somebody's pocket
  • line your pocket
  • line your pockets
  • for (one's) (own) sake
  • for sake