Spain is continuing its experiment with free suburban rail. In major cities, you can get a season ticket for a four month slot on the city-wide local trains.
It doesn't cover the intercity services which stop at the suburban stations.
As a reality check, they charge a €10 deposit for the ticket. You lose that if you don't make 16 trips but if you do, the money goes back to your account after the date slot has ended.
Around just 3 trips and you break even.