Free walking tours

My daughter and I enjoyed our “free” walking tour in Lisbon (2019)
I found out about the tour at the tourist information office the day we arrived and booked it online. It’s not actually free as the tour guides are usually college students who are trying to make a little money.
At the beginning of the tour, the guide explained that they have to pay the TI a price per person and then they get to keep the rest. In our case I think the guide had to pay €4 per person. The tour lasted 2.5 hours and we thought she did a good job so I gave her €40 for the two of us.
Everyone gives what they choose to give.

Enjoy your time in beautiful Portugal!

It should never be advertised as a "free" tour if you are expected to pay for it by tipping the guide.

Just one more way to scam tourists.

Tours where you pay up front are honest, "free tours" are not.

I do an internet search for Free Tours before arriving in the cities I am interested in touring and pick one that fits for us. We have always been pleased with the result. I expect to give a tip at the end. I see that expectation disclosed in the tour information so it is not a surprise.