Free walking tours of Granada are very popular. They could be free if you are very mean and  you don't give a donation.
They could be called voluntary donation tours or crowd sourced tours.  I am sure that a guide working for voluntary donations at the end of a tour  would be quite good because if not they would have to change jobs very quickly.

There is normally a meeting point and if enough people have signed up the walk goes ahead.
If you would like to sign up for a free tour Click Here
 
Free Walking Tour of Granada
At the indicated time the tour meets in plaza de Bib-Rambla to begin a two hour exploration of Granada, a city with long history both Christian and Muslim, with the sweet smell of incense wafting around every corner and the sounds of flamenco drifting through the streets.

From the "Fountain of the Giants" which can be found in the square, we'll lead you round the Granada Cathedral, the old silk market (or Alcaicería as it was known in the Emirate of Granada) and the Royal Chapel, where the bodies of Spanish Monarchs Isabel I and Ferdinand II still lie.

The tour will immerse you in the very soul of Granada, with its unique atmosphere easy to feel in the streets, squares and buildings with Gothic and renaissance touches. And you'll feel transported back to the time of Muslim rule on our tour around Albaicín with its narrow winding streets dating back to the time of the Nasrid Kingdom.

Our free tour of Granada finally ends in Plaza de Santa Ana.

You Decide the Price
Our guides exclusively work for tips from their guests. At the end of the tour, you can decide the price the service deserves.

Important
Children should come accompanied by an adult, with a maximum ratio of 3 children per adult guest

If you would like to sign up for a free tour Click Here