walking tour of Helsinki

I am currently in Helsinki. I reserved a two-hour walking tour through Red Umbrella Tours. They use a "free tour" model. Our guide was an engineering student; he was very knowledgeable and kept the group of 12 moving but didn't rush us. April 30 and May 1 are major celebratory days for Finnish university students, and he was good at filling us in on some of the traditions. From what I observed the "tip" paid by members of the tour group ranged from €10-20 per person.