an arm and a leg vs low-priced

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 

low-priced

adj
  • Having a low price; cheap. 

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