I pay Three £15 p/m for unlimited data, lots of intra-Three calls and some messages/calls to other networks (in the country I'm in at the time) and can now do that not just in the UK but in Spain, the US, Australia and more (http://www.three.co.uk/Discover/Phones/Feel_At_Home). That's cheaper than most local operators and a much better example than whats offered here.
I'd wager it won't be long before Three sims are being picked up by tourists and used as their main operator back at home.