Hello and welcome on this forum. But ..... we are not travellers, we are pilgrims or at least Camino walkers. And a good Camino needs a good preparation. Therefore you are here at the right address: use the search button in this forum, spend a few hours and you will be overloaded with more info than you ever expected.
Your Portuguese friend certainly was wrong with his information about 'staying the night for free'. On many Caminos one can find 'donativo' albergues, but donativo definitely does not mean you don't have to pay! You use water, toiletpaper and electricity, you use the facilities, the host makes you feel very welcome and the next morning he or she has to clean the place for new guests ........
In average in a donativo albergue one pays € 10,-- for the night if everything (bed, shower, toilet) was OK.
Here in the Netherlands where I live we have a saying: 'Only the sun rises for free' and that is so true! If many people think that a 'donativo' albergue means 'sleeping for free', the famous and warm hospitality we all experience on the Camino will eventually disappear, much to our regret!