The costs depend on group size and ambition. Intimate anniversary (50 people): 5,000 to 15,000 euros. Mid-sized (150 people, special venue): 15,000 to 40,000 euros. Large (300+ guests, full production): 40,000 to 100,000 euros or more.
Many original ideas cost no more than standard ones. An escape room, handwritten letters or a time capsule add value without extra budget.