unvaluable

From un- +‎ valuable.

unvaluable (comparative more unvaluable, superlative most unvaluable)

2. (rare) Not valuable; having little value. [from 17th c.]

   Synonym: nonvaluable

   Coordinate terms: valueless, worthless; inexpensive

4. (obsolete) Invaluable; beyond price. [16th–18th c.]
   • 1603, Michel de Montaigne, chapter 4, in John Florio, transl., The Essayes […], book II, London: […] Val[entine] Simmes for Edward Blount […], →OCLC:

     I kon him thanks that he hath had the hap to chuse, and knowledge to cull-out so worthy a worke, and a booke so fit to the purpose, therewith to make so unvaluable a present unto his Countrie.