You'll need a team to do searches, but it can be a free team:
Go to your Team Center page, and click on Start New Team. Next, join an Exhibition League, which is free. Once you register for that, you'll be able to enter the Draft Center, from where you can conduct searches.
By the way, you never have to actually enter this team into an Exhibition League. You can keep it in your Draft Center forever. It can come in handy there.