SIM Card in Barcelona
Nowadays having a mobile phone with internet is almost as important as food. Like everywhere else, you have basically two options: an indefinite contract or a pre-payment contract.
My recommendation is easy: if you plan to live in Barcelona less than two years, it is better pre-payment cards. The price per minute is a little bit more expensive, but it is much more easy to get a contract or canceling it. Besides, unless you call a lot (nowadays it is not very common having whatsapp and Social Media), it is even cheaper.
Regarding the telephone companies, there are a lot in Barcelona with different prices and rates, but the biggest ones are Movistar, Orange, Vodafone and Yoigo.
I won’t detail the rates because they vary a lot, but generally speaking you can pay monthly from 5€ (pre-payment) to 30€ (all included, by indefinite contract).