a dime a dozen vs pinchbeck

a dime a dozen

pinchbeck

adj
  • Made of pinchbeck. 

  • Sham; spurious, artificial; being a cheap substitution; only superficially attractive. 

noun
  • An alloy of copper and zinc once used as imitation gold for cheap jewelry. 

How often have the words a dime a dozen and pinchbeck occurred in a corpus of books? (source: Google Ngram Viewer )