Either it is a walking tour or a bus tour, it is appropriate to tip your guide with at least one euro per person, depending on how long the tour was. If it was a bus tour, maybe you'll want to give one euro for the driver and one or two for the guide (it's best to give each their tip, as not always they'll be sharing).

Tipping etiquette in Spain is generally more relaxed than in North America, but it is highly appreciated for good service. For a standard group bus tour, it is customary to tip the driver approximately €1 per person per day. If you are on a half-day excursion, a smaller gesture of 50 cents to €1 is sufficient. However, for a private chauffeured tour or a long-distance transfer, the expectations are higher; travelers often give €10 to €20 for a full day of service, depending on the driver's helpfulness and local knowledge. If the driver assisted with heavy luggage or acted as a secondary guide, leaning toward the higher end of the scale is polite. It is always best to tip the driver in cash (Euros) directly, as they often do not share in the tips given to the main tour guide. While not strictly mandatory, this gesture is a standard way to acknowledge the driver's role in your safety and comfort throughout the trip.