So, the first thing you do is grab a prepaid SIM card and a cheap phone. You can find them at most electronics stores or online. Then, you just pop the SIM card into the phone and activate it - no contract, no commitment!
You'll notice right away how liberating it feels to have a phone that's not tied to your real name or address. You can use it for anything, from messaging friends to browsing the web, without worrying about being tracked.