NEW YORK (CNNMoney.com) - Today is the deadline to sign up for the Medicare Drug Plan.

If you're one of the 5 million eligible Americans who still haven't chosen a plan, today's 5 Tips will tell you what you need to know.

You have until midnight tonight to sign up for a plan...or face the consequences. In this care, it means penalties that will last as long as you have your health plan: one percent of the premium every month for the life of your plan.

The next opportunity to enroll is Nov. 15 and then your coverage will begin in January 2007. That means you you'll automatically be paying 7 percent on top of your premium. The enrollment process shouldn't take more than half an hour according to Health and Human Services.

But keep in mind there are exceptions. Hurricane Katrina victims will have until December 31, 2006 to enroll in a plan without penalty. You can also get an extension if you've moved into or out of a nursing home.

You will also qualify for an extension until the end of the year if you meet income requirements. If your annual income is less than $15,000 ($20,000 for couples) and your resources are less than $11,500 ($23,000 for couples), you'll be able to get some extra assistance from the government.

If you think you might qualify for the extra help, you can complete an online application at www.socialsecurity.gov.

In some states, there can be 40 different Medicare plans offered. But you have to tune out the noise and get the bottom line.

The most important feature of the Medicare plan is the group of medications it covers. If the drugs you take are not in the plan's formulary, skip it. Go to www.medicare.gov and plug in the medications you're currently taking. The Web site should list the number of plans in your area that you should compare carefully.

Make sure you note any restrictions. Some plans may limit the quantity of medicine that you take. If you have a history of a certain condition in the family, you may want to see if it's in the family of covered medications. That's because if your medications change while you're in the plan, you can't switch out until the next enrollment period.

Companies are spending millions and millions of dollars on marketing because there is so much competition between plans, according to Juliette Cubanski of the Kaiser Family Foundation. So it's a good time to watch out for scam artists.

Never trust anyone who asks for money to enroll you or who demands any payment up front. If you suspect a scam, call the Centers for Medicaid and Medicare Services at 1-877-772-3379.

No one should call you and ask for your financial or health care information. You should not be getting any e-mail from companies, says Gary Karr of the Centers for Medicare and Medicaid Services.

Time is running out so you should try to enlist as much help as possible. You can call Medicare at 1-800-633-4227 or use the Web site at www.medicare.gov.

For one-on-one counseling and assistance in person or on the phone, look up your State Health Insurance Assistance Program, or SHIP at www.shiptalk.org. You can also go to your local area Agency on Aging for more specific information about your state. That Web site is www.eldercare.gov or call 1-800-677-1116.

The Medicare drug plan was designed to save you money. But you still have to be vigilant when it comes to cutting your overall heath care costs. One big money saver: scrutinizing your hospital bill.

Over half of medical bills have mistakes. These mistakes can range from a complex insurance coding problem to a simple typing mistake. Don't get stuck paying for a mucus retention system, aka tissues.

"Even one very small error can balloon," says Susan Dressler from the Alliance of Claims Assistant Professionals. Never pay your bill before leaving the hospital, she says. And request an itemized bill, since the hospital won't automatically send you one.

Here are some troubleshooting spots: Make sure the dates are correct. Then compare the charges on your bill with the doctor's orders. Hospitals may bill a patient for a procedure even though the doctor cancelled it. Room fees may come with à la carte extras. Make sure you're not paying for sheets or towels.

If you disagree with any charges - or don't understand all the Medicalese - call the hospital's billing department. The billing office should provide a detailed bill for free within a month. Remember, you have rights under "A Patient's Bill of Rights" published by the American Hospital Association. This document states you have the right to know what a hospital charges for services.

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Gerri Willis is a personal finance editor for CNN Business News and the host for Open House. Send your questions, your comments and your own ideas to us at 5tips@cnn.com.