"PRICELESS MEMORY"

1: Having a value beyond any price : INVALUABLE
priceless
adjective
price·​less ˈprīs-ləs
: costly because of rarity or quality : PRECIOUS
2: Having worth in terms of other than market value
3: Delightfully amusing, odd, or absurd
pricelessly adverb

so precious that its value cannot be determined:
"priceless works of art"

INFORMAL
used to express great and usually affectionate amusement:
EXAMPLE: "darling, you're priceless!"