Mail from Vodafone reads ...
"For the price of an ice cream, you can use your UK minutes, texts and data in Europe like you would back home. It's just an extra £3 a day."
... they're buying their ice-cream in the wrong place.
You can get four mint choc chip cornettos for a quid from most shops. That's 25p per cornetto. In real money that means I could buy twelve cornettos for every one that Vodafone buys.
I think we know who's the real winner here. It's me. That £3 I'm saying every day can go on ice cream instead, and I never have to leave the house. I'll grow enormous through continually eating nothing but cornettos, but financially it will still be a saving over the inflated prices they want to charge me for using the phone services already paid for.
It could be called ... economnomics.