Oops, it doesn't look like 'sale day' is a national day..

Other days

book

Book Day
brow

Brow Day
buddy

Buddy Day
bonang

Bonang Day
slime

Slime Day
ormille

Ormille Day
bounce

Bounce Day
tulip

Tulip Day
pampering

Pampering Day
boba

Boba Day