Can these work for using the internet in spain and if so how would it work money wise.

 

The rates are here: Standard rates and data costs - International - O2 (basically the same as mentioned above).

I was travelling last week and got a text message as I entered each country saying that data would be charged at £4.99/day for up to 25mb (which is still extremely expensive), so I don't know if they are running a special offer?

Steve