A number of companies are starting to offer consumers free peeks at their credit scores, and not just their credit reports. That’s handy because it’s the score that lenders use to decide how much to charge in interest and whether to approve you for loans or credit cards.

You can get free credit scores at eloan.com, creditkarma.com and credit.com. The hitch is that they offer scores devised by the credit-reporting companies, mostly Trans-Union and Experian, and not the most widely used score developed by Fair Isaac Corp. (FICO). It will still cost you $16 to get a copy of your FICO score at myfico.com.

Why bother? If you’re getting ready to borrow money, your score can make a big difference—particularly in the current tight economy. A high score (760, say) can save you about $250 a month in interest over a middling (650) score on a 30-year fixed rate $300,000 mortgage.

It’s a good idea to check your detailed credit reports once a year. You can do that for free, without any strings attached, at annualcreditreport.com. Monitoring your credit report more often (at companies like the heavily advertised freecreditreport.com, which charges $14.95 a month) won’t prevent identity theft. Signing up for regular credit monitoring is just asking for a marketing blitz, says Steve Elias, an attorney with legal publisher Nolo. “Once you have identified yourself as someone who’s operating in fear, you’re a sitting duck for all those extras” like Internet security monitoring and lost wallet insurance. That’s one more reason to stick with the free services.