Doing Interrail on a budget in 2026 requires strategic planning and a focus on "Eastern" routes. First, purchase your pass during the annual "Early Bird" sales (usually in March or late autumn) when discounts of 10% to 15% are common. To save on daily costs, prioritize countries in Central and Eastern Europe—such as Poland, Hungary, Romania, or the Czech Republic—where food and accommodation are significantly cheaper than in France or Switzerland. A major "money-sink" to avoid is mandatory seat reservations on high-speed trains (like the TGV or Eurostar), which can cost €10 to €30 per leg. Instead, use the "No Reservation Required" filter in the Rail Planner app to find regional trains; they take longer but are free with your pass. Finally, consider taking overnight "Nightjet" trains; while the couchette has a fee, it saves you the cost of a night in a hostel or hotel while moving you to your next destination.