UK, MiFi: 1Gb a month costs 10 GBP == 11.77 EUR.
And a pay-as-you-go phone for the occasional phone call. I pretty much only use my phone to arrange lifts, book cabs etc. The legacy voice network probably costs me about 1 or 2 GBP a month in call charges on pay-as-you-go. And my legacy phone is completely unlocked.
Legacy voice phones are for calling the police if someone is in a car accident, and occasional interfacing with weird people who haven't quite grasped the whole Internet thing. For everything else, I just use TCP/IP (and often Skype), and for that 1Gb is more than enough. Anything that requires heftier bandwidth? Pop open SSH and tell my machine at home to do it.
So basically, I'm probably using the same amount of data as the smartphone users, but I can use that on any device that supports wifi. And I pay less than if I had a contract. The only downside is I have to carry a phone as well as a dongle. But I carry a bag with me everywhere.