an arm and a leg vs plush

an arm and a leg

noun
  • Usually used after the verb cost, but also often charge, pay, and spend: a very high price for an item or service; an exorbitant price 

plush

noun
  • A textile fabric with a nap or shag on one side, longer and softer than the nap of velvet. 

  • A plush toy. 

adj
  • Having a soft, fluffy exterior. 

  • Very extravagant. 

  • Very expensive, or appearing expensive; opulent, luxurious. 

How often have the words an arm and a leg and plush occurred in a corpus of books? (source: Google Ngram Viewer )