It's not hard to find an offer for a free credit score. Do you get what you pay for?
Most 'free' scores are either trial offers that you'll need to sign up for (and remember to cancel if you don't want to pay a fee in the future) or they aren't real credit scores.
There are a variety of credit scores out there. The most important and useful one is the one your lender is about to use when they decide what to do with your application. In most cases, this is a FICO credit score.
Some websites have come up with credit score simulators and estimates, sometimes referred to as FAKO credit scores because they aren't real FICO scores. Can you get any value out of these services? Andrea Coombes at MarketWatch.com recently took a look at what they said her about her credit.
The numbers you see are probably not very useful, but the services may provide some guidance. They can help you identify problem areas, such as high debt utilization, a lack of variety in your borrowing history, and more. They use assumptions that are (hopefully) similar to those used for your FICO credit score calculation.
If you're just curious about your credit, you can get a little advice from credit score simulators. However, remember that your lender gets to choose which credit score to use.
Further reading:
Those free credit scores like the one from CreditKarma.com can be useful when you just want a general idea of where you stand but consumers should definitely get a FICO score if they’re applying for major loan within the next 12 months.