For someone who has access to wifi most of the time and need internet access on rare occasions where wifi is unavilable, the cheapest solution would be Boostmobile. For around $7 per month ($3.5 if "$10 for 3 months" reboost can be found) you get some minutes (which I don't use) and free internet access through iDEN network. You get dial-up speed, not broadband, but I used it exclusively (no wifi connection) on a 2 week vacation recently and managed to get connected, patiently