No, it's up to the owner of the router to decide whether to secure it, charge money for access, or leave it open and free, because they are liable for the actions of anyone using their internet connection. There is nothing you can do to magically make it free, or create free wifi out of thin air. You have to be near a hotspot that is designated specifically to be open and free.
You might find one at McDonald's or Starbucks, among other places, which of course will usually expect you to buy something while you're there. There are several apps in the app store that will help you find free wifi hotspots too.
Something you should be aware of when using unsecured wifi: passwords and other sensitive information that you transmit go over unencrypted signals that anyone else using that router can see with the right tools. So, I would think twice about using a router that has no password.