There are several cheap Internet cafés in town.
In Cagliari, the town is at walking distance from the port. No need for any kind of motorized transportation! The port authorities took us to the boulevard on a free shuttle coach, as they did not want pedestrians walking through the port, but distance-wise this was absolutely not necessary. The boulevard with upmarket department store Rinascente is good for a nice stroll, but beware of pickpockets. The little streets of the old town are an absolute delight.
There are several cheap Internet cafés.
Malaga is the gateway to the famous Costa del Sol with large sandy beaches. If beach is what you want, there is a modern train leaving from the main station every few minutes. The old town of Malaga is absolutely lovely and the old Moorish castle is worth a visit. On the main road out of the city is the huge department store El Corte Ingles, for those shoppers among you.
If you have a chance to go to Granada or Cordoba, DO! These tourist attractions are definitely among the most famous in Spain. The only problem is that because of crowd control, the Alhambra in Granada now issues tickets with time slots. So even if you get there early, you might not be able to buy a ticket for the time you want or even for the same day! That is why in this case a tour could be advisable. Also because it takes you all day to get there and back, and with an official tour, at least the ship will wait for you.
Cadiz is a drop dead gorgeous city with little streets, lots of history and beautiful affordable shops. You do not need a tour, there are several walking routes that are indicated by a coloured line drawn on the pavement. At every interesting point, there is a large sign in Spanish and English with a lot of background information. The town is compact, easy to walk and surrounded by the sea on 3 sides, which makes that you can never get lost as it is easy to keep your bearings.