Check into opening up a single member LLC. You'd have to do a bit of research for the area (state/country) that you live in, but in doing so, obviously you're creating a business, and the business can sign up to Adwords. If you want to use a different address for the business, see if there is a UPS store near you, they will allow you to rent mailboxes that have an actual street address (not a P.O. Box) and you can use that for the biz. Hope that helps!