Priceless
Pronunciation : Price"less
Part of Speech : a.
Definition : 1. Too valuable to admit of being appraised; of inestimable worth; invaluable.
2. Of no value; worthless. [R.] J. Barlow.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder