Tuenti is one of the best SIM cards for visitors to Spain. If an existing Tuenti customer introduces a new customer, then the new customer receives €10 free credit.
The SIM card costs €10 as usual (which is sent by post to any Spanish address), but gains an extra €10 of credit. For example, pay €10 for a new SIM with a 1GB €7 bundle, and you will have €13 of credit left over after the €7 bundle is deducted. Tuenti accepts non-Spanish credit cards and you can order the SIM to be sent to your hotel or other accommodation.
If anyone would like a referral code to be introduced as a new Tuenti customer and receive €10 free credit, please
send me a PM.