For the most part, as the saying goes, there is no such thing as a free lunch, or a free latte. This is all too true, I'm afraid: Mostly you will need to pay to surf while you sip.
With most Wi-Fi service providers, you don't need to sign up for a plan, although it will certainly be beneficial for you to do so if you plan to make much use of the service (Chapter 12 has more information on making the best of the economics of the matter). You also don't need to enroll with a Wi-Fi service provider in advance. You can do it on the spot when you connect via your laptop (provided, of course, you've brought a valid credit card).
If you're just looking to get your feet wet in the pool of connecting to the Internet through a public ...