Spain is a very beautiful and innerly different country. From the very Mediterranean, almost Arabic, Andalucia to the very proudly autonomous regions (or countries according to many of their inhabitants) like Catalunya, Euskadi (Basque country) and Galicia in the North.
Spanish people are usually not very talented speaking foreign languages which makes your life much harder if you don't speak a basic Spanish.
There is a big counter culture, from the "acampadas" (occupy) movement, to many ecovillages and communities all around the countries. Especially the south, can be very hot in summer (the whole country actually), but nicely warm in winter, making it a good idea for Winter retreats. It is generally quite a good place for nomads.
Hitchhiking in Spain sometimes might be not so easy. However, the meaning of the thumb will be very easiful understood, though probably the best method will be asking people directly whenever possible, even if your Spanish is very poor.
Wild camping should be theoretically illegal, though practically much more than tolerated. As usual, the less you stay and less you let others notice you, the easier will be.
Dumpster diving at supermarkets and openmarket works usually well. Asking also is often a good idea.
Wifi quite well spread everywhere. Internet cafes also
Depending on the cities. Euro currency but not so high average income. Quite good anyway but not as continental/northern europe though. Approximately the same as most of Mediterranean Europe.
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