(MONEY Magazine) – In an attempt to offer employees extra benefits for next to nothing, an increasing number of companies are helping workers buy insurance policies ranging from term life to prepaid legal services. Your boss picks an insurer and, in some cases, negotiates a low group rate. All you do is pay the premium through automatic payroll deductions. "They're feel-good benefits," says Dallas Salisbury, president of the Employee Benefits Research Institute in Washington, D.C. "They're a very low cost to the employer, but they make employees say it's a great place to work."

Yet--as with eating fast food or taking the escalator instead of the stairs--just because something is easy doesn't mean it's your best move. If your company rolls out voluntary insurance benefits, ask yourself two questions: Do you really need the coverage, and if so, is the offer the lowest price you can get?

The best deals are likely policies you couldn't buy as an individual, such as legal or dental insurance. With prepaid legal services, for example, you pay $15 or so a month for access to a network of attorneys who'll help you with pretty much anything except lawsuits and complaints against your employer. This type of policy may make sense if you expect to need basic legal advice soon, perhaps if you're buying a home or drafting a will. Major corporations offering such plans include Microsoft and Kraft Foods.

When it comes to life and auto policies, your boss may or may not have the best deal, depending in part on how high a risk you are to insure. Since an employer's group life insurance rates are based on a large pool of workers, a young nonsmoking employee might get a better deal as an individual, says Robert Sollmann, a senior vice president of Metropolitan Life Insurance. Similarly, a driver with a spotless record might do better on his own. To analyze any policy your employer offers, get independent quotes. Two good websites for auto and life insurance quotes are www.quicken.com and www.quotesmith.com. --BEVERLY GOODMAN