You can monitor your own credit for free.
Yes, you can. But you can only get one credit report PER YEAR free. You probably could get one free from each of the 3 credit reporting companies, so effectively, you would get 3 reports per year, but who is to say that each report contains the exact same info?
The Equifax, TransUnion and Experian credit reports do typically contain different info and are formatted differently. The information is different because they each acquire it from different places.
Also, once you get a credit report, do you know what to look for? How do you tell what is suspicious, and what is business as normal?
They contain a list of your home addresses, typically with a bunch of bogus entries that are a mix of two valid addresses, or entries where letters or digits were transposed. There's also a list of your credit accounts, current status, account open/close dates, along with entries if you've been 30, 60, 90, etc. days past due. Just have them remove the bad addresses and look for any accounts you didn't open.