YOU are your own credit monitoring service (and all it costs is time)
I know "free" services always come with a catch -- your attention is sold to advertisers, usually -- but by using the following, I've kept decent tabs on everything before I had an official monitoring service (see notes 1 and 2):
First, I use AnnualCreditReport.com to check and print (hardcopy) and sometimes download (PDF) the official reports from the main three agencies.
Second, I use CreditKarma to get updates to two of those three just about whenever I feel like it, up to weekly. I aim for monthly, but I don't always go through the trouble unless I know something is coming like we intend to apply for something.
So when the press says "[company] is offering credit monitoring services for anyone affected", I usually move on, since I KNOW my credit reports haven't been affected (note 4).
Bootnotes:
1. Like others, I do have OPM MyIDCare (check my nickname and add it up); go back up to SotarrTheWizard's post about it.
2. Even though it doesn't help much, I'm glad I had it in place so this extra Equifax hurdle was cleared in a couple minutes.
3. Everything I've been doing I also do for my missus; equally protected.
4. I have had one certain credit card misused twice, but only found out through that card's own site (recent card activity) on my own. Their own fraud prevention didn't catch it, but they were great at reversing charges immediately and issuing new cards without disturbing my credit/payment history or any other terms. I mostly blame myself for username/password reuse, which I've rectified in a manner unique from any other recent password changes, but it is possible the card details were stolen from any number of retailers.
Regardless of the cause, my main point stands: it was/is my own diligence that kept/keeps nasties at bay. Everyone needs to take responsibility for their own financial presence, physical (cash, checks, cards) or digital (credit reports/scores, online accounts and login credentials) -- own it!