Yes, you will pay for their services. But, identity theft protection services can help protect you far better than you can protect yourself online. Not only do they watch for noticeable threats, but also those you would never think exist.
They will also alert you when something is wrong, when information such as your address is changed, and whenever new accounts are opened. Additionally, many services send out regular reports, and keep you updated, to ensure you are the only person using your personal information.