Just bought a SIM from the electronics store at the airport (to the right on exiting T2). The salesclerk told me the cheapest was Blau and it was E20 for 1 gig of data. The card pack said it was E9.90 so the clerk alleged the remainder was a "startup fee." I think I was lied to and I also think that Blau, which uses the E+ network, is nothing special as well.

Please tell me I am wrong and the guy was honest! Travel involves constant petty ripoffs but it always annoys me way more than it should when I am caught in one.