New price includes chemist's third formula (6)
I believe the answer is:
recipe
'formula' is the definition.
(synonyms)
'new price includes chemist's third' is the wordplay.
'new' is an anagram indicator.
'includes' indicates putting letters inside.
'chemist's third' becomes 'e' (3rd letter of 'chemist').
'price' anagrammed gives 'rcipe'.
'rcipe' going around 'e' is 'RECIPE'.
(Other definitions for recipe that I've seen before include "A baking formula" , "List of ingredients" , "Directions for cooking the turkey e.g." , "Formula for making something" , "Directions for making a dish" .)