Buy a $2 notebook.

If you’re looking for a #bitcoin based one. 🤙 nostr:note1kynwt2gvg4w2zf57erzl0cfzfcy9dz9pdhjw3f068r92zlhk4wcqjwgarj

Iexpenseit. Been using it 7 years continuously

Been using money wallet for years https://f-droid.org/packages/com.oriondev.moneywallet