bargain basement vs shopping centre

bargain basement

noun
  • An area within a retail store, especially an area located below ground level, where the least costly merchandise can be found. 

  • Inexpensive. 

  • Of poor quality; of little or no value; low-end, shoddy. 

shopping centre

noun
  • A large retail outlet consisting of several shops. 

How often have the words bargain basement and shopping centre occurred in a corpus of books? (source: Google Ngram Viewer )