SIM card for Android phone

I went to a Vodophone store in Alciente Spain and Lisbon Portugal. Less than 15Euros, but depends on how long you want to use it. Google Vodophone in Barcelona.

For more information on SIM cards, a great source is Prepaid GSM. Here's their Spain page: http://www.prepaidgsm.net/en/spain.php

If you have questions, their Forums have lots of details (and I do mean DETAILS - don't be afraid to ask for clarification, as the discussions can get very technical): http://www.prepaidgsm.net/forum/forumdisplay.php?f=22

You can buy sim cards at the airport, but you don't get the best deal. If you can, wait until you get into the city. They are sold everywhere! Orange, Tuenti and Vodafone are a few of the more popular. I bought an Orange prepaid sim for $10 euros which gave me 1 gb of data good for one month, and calling minutes and text. I also bought a Tuenti card for the same amount (two different phones) I find Tuenti very difficult to recharge - they are internet based only. There are Orange places everywhere. You can also go into PHONE stores where you can choose. Basically though, Orange and Tuenti are the ones that offer no contract, prepaid, short term cards for $10 euros. Vodafone was almost $20E.