Get Comfortable Lying
I've read that the average American lies 25 times a day. I don't know how you would test that, certainly not by a survey, but I can believe it. Those lies, mostly, are little white lies. Slight embellishments on the truth. Despite that, Americans place a very high value on truth. On the playground, the worst charge one child can make against another is, "he's lying!" Political scandals center not on national security, not even on sex, but on honesty. One lie can end a politician's career. Your culture has a love affair with the truth, and because of that, most people are pretty bad at lying. You need to get good at it, at least in defense of one specific area, your privacy.
People are going to ask you all day where you live. When you go to the doctor, try to get a mailbox, try to get a cell phone or a pager, when you are interrogated by the police, when you want to join a supermarket club, when you want to get a storage unit, they'll ask. They'll want your home phone number, too. If you don't provide these pieces of information, and prove you are a member of the housed public, they will deny you services.
You don't have any time for that. You have problems you are solving just as fast as you are able, and the last thing you need is to be arguing with some salesman about the fact that the reason you want a cell phone is that you don't have a phone. They don't care. They just need you to fill in the little box on the form. So make up a phone number. What are they going to do, check?
Even in the unlikely event that you were caught, it's meaningless. It is perfectly legal to lie to the clerk at the grocery store. The worst they can do is deny you services, which they would have done if you told the truth.
You are a member of the counter culture now. Welcome. Truth is a value of the culture your life is running counter to. You're going to have to get comfortable modifying that value a bit. Your private life must be kept private. Lying defends it.
Lying is a survival skill.