I’ll be arriving in Madrid 16.5. to walk from Pamplona from 21.5. I’d like to buy a SIM card ASAP on arrival in Spain. Would like to have some data and be able to text n call. Can somebody recommend where to get a reasonable priced SIM? Is it better to buy at the airport or a provider in Madrid city? Been told that Vodafone has a €20/mnth deal with 2G data. Don’t really need that much and rather pay less. Any recommendations?