costly vs pricy

costly and pricy both are adjectives.

Word	Noun	Adjective	Verb	Adverb
costly	No	Yes	No	No
pricy	No	Yes	No	No

As adjectives, costly and pricy are synonyms defined as:

Other synonyms of costly include dear, high-priced, pricey.

costly (adjective)	pricy (adjective)
having a high price	having a high price
entailing great loss or sacrifice