Tap Water: Finland has the absolute cleanest tap water in the world. Bring a reusable bottle and never buy bottled water!
Lunch Buffets (Lounas): Many high-end restaurants offer spectacular lunch buffets on weekdays for just €12-€15. Eat heavy at lunch and light at dinner.
Book Early: Intercity train tickets (VR) and domestic Finnair flights are significantly cheaper if booked 2-3 months in advance.
Everyman's Right (Jokamiehenoikeus): You can roam freely, forage for wild berries/mushrooms, and camp in most forests entirely for free.
Museum Card: If staying long in Helsinki, buy a Museokortti (Museum Card) or Helsinki Card for bundled savings on attractions and transport.