at a premium vs priceless

at a premium

prep
  • At a high, or higher than expected, price. 

  • Scarce, in short supply. 

  • Above par value. 

priceless

adj
  • Treasured; held in high regard. 

  • Without a price assigned. 

  • Very amusing, hilarious. 

  • Ridiculous, absurd, rich. 

  • So precious as not to be sold at any price; invaluable. 

  • Excellent, wonderful, fantastic. 

How often have the words at a premium and priceless occurred in a corpus of books? (source: Google Ngram Viewer )