There's only one tragedy greater than standing in your driveway on Saturday at 6 a.m. selling your Stairmaistro TX5000 for eight bucks to an early-bird shopper, and that's to still be making Visa payments on it afterwards.

That's exactly what will happen if you pay by the guidelines put forth by your purveyor of plastic, otherwise known as "Paying the Minimum Amount Due."

Rule No. 1: Always pay more than the minimum amount required. A lot more.

Fools don't pay by the lending industry's standard rules. Revolving credit cards (unlike charge cards such as American Express, which requires you to pay the full balance each month) require a minimum payment of just 1.5% to 2.5% of your outstanding balance each month -- a calculation cleverly designed to prevent you from paying off your balance before your grandkids' grandkids celebrate their Bar Mitzvahs.

Seriously, pay by their rules, and it'll take you 44 years and one month to pay down a balance of $4,500, even if you don't put another penny on the card once you reach that limit.

And how much will $4,500 in culottes, New Kids on the Block CDs, and products guaranteeing they'll help you shed the extra weight end up costing? About $17,000. If that doesn't make you drop 20 pounds, we don't know what will.

Rule No. 2: Keep your eye on the interest rate.

How come it's possible to pay off a mortgage during your lifetime, but your credit card balance can last well into the next century?

The way interest rates are calculated in the credit card business is different than those used by lenders on the mortgage side of the business. Mortgage loans are amortized over a fixed term, say, 15 or 30 years. The terms interest rate and balance are used to calculated a fixed payment that results in the balance being paid to zero after the specified number of payments.

Credit card issuers, on the other hand, use a baffling, complex system of pulleys, ball bearings, mirrors, and Boolean algebra to calculate your finance charge. In the end, most come up with a figure somewhere between 0% to 32%.

OK, we'll get serious for a moment. Credit card debt is open ended -- meaning there's no fixed term. Determining the terms of your loan is a numbers game for the industry. Looking at the population as a whole, they set your minimum payment based on what makes them feel comfortable that you can handle the debt and won't default on your loan.

Obviously, some borrowers will be unable to pay back their loans. And guess who pays for the deadbeats? That's right -- you. Credit card issuers set the rates higher for everyone so they can cover expected losses.

The interest rate is the Rosetta Stone for those trying to pay down a balance. Watch it closely.

Some banks charge a "fixed" APR (annual percentage rate), while others charge a "variable" APR, which is tied to an index, such as the prime rate. For a more detailed rundown of interest rates, check out "Interest Rates 101." The Schumer Box -- which must legally be included on every credit card solicitation -- contains all a card's vitals. If you can't figure out your card's APR by looking at your monthly statement, read "Interest Rates 101" or call the customer service number for a translation.

Rule No. 3: Pay down your credit card debt before you invest.

Bar none, the best financial decision you can make is to pay down your debt -- before you even start investing. Ask your kid, your niece, or the tike behind you in line at the grocery store, "Which sounds better, losing 18% of your cash a year, or making 12% on every buck you sock away?" Go ahead. We'll wait.

In fact, while we're waiting, we'll do the math. Take an investor who comes into a sudden $3,000 windfall. Although she has $3,000 in debt, she has heard about the great returns she can get in the stock market (well, at least the returns that folks got a few years ago). If an average year on the stock market pushes her holdings up 12% (we're being extremely generous here), can she beat the 18% growth rate on her debt? Nope.

A decade later, her debt has grown to over $15,000, and her investments have grown to over $9,000. Though she started with enough money to eliminate the debt, she's now in the hole over $6,000 -- until she sells those stocks. Then she'll have to pay 30% of the profit back to the government in capital gains taxes. So she's actually out more than $9,000.

Rule No. 4: Make every point matter.

In this instance, we think the numbers speak louder than any lavish prose we could compose. So here, in all its glory, are the gory details of what it will take to pay down eight grand at four different interest rates, paying just the minimum balance each month.

Just to state the obvious (we Fools occasionally do that, you know), it appears that the interest rate plays a somewhat significant role in your debt load. If you currently carry a balance, it behooves you to make sure you are paying as little interest as possible. In fact, the first place we suggest you look for a lower rate is right in your wallet. It's not always necessary to go to a new issuer to get the most competitive interest rate. Read on for ways to work out a sweet deal with your current lender.

Rule No. 5: Ask for a lower rate. Really, just ask.

If your current lender is charging you more than 12% interest, it's time to re-neg-oti-ate, Fool. Use our Foolish Rate Negotiation Dialogue (tm) below to kindly convince your lender to lower your interest rate.

Hundreds of Fools (Really! We've counted!) have used this tactic to get points knocked off their interest rates, earning them years of freedom from repayments and countless dollars in interest payments. According to a survey conducted by the U.S. Public Interest Research Group (or PIRG, for those in the know), more than half of the study's participants who called their credit card company were successful in reducing their annual interest rates by an average of one-third.

And what a difference one phone call can make: Rachel Heller, one of the 50 consumers who participated in the survey, was able to cut her APR almost in half, from 15.9% to 8.65%. With a balance of $4,474 and making the minimum payments of 2%, Heller saved herself $324 in just the first year and $5,031 over the life of the debt. Because of her lower APR, she will also pay off her debt almost 10 years earlier.

Why does this tactic work? One reason is that the lending industry is filled with competition. The market is saturated with credit card offers (you might have noticed, ahem). According to CardWeb.com, more than 80% of U.S. households have at least one credit card. And the average card-carrying Jane already has eight credit cards to her name. Your lender would rather keep you as a paying customer -- albeit at a lower interest rate -- than shell out anywhere from $50 to $150 to acquire a new customer.

Use your leverage and get your lender to lower your interest rate (and waive a few fees, while you're at it).

Foolish Rate Negotiation Dialogue (tm)

Pour yourself a latte, affect your best French accent, and use this handy Foolish Rate Negotiation Dialogue to start saving, big time:

You: "I just got this incredibly great offer from First Union Banc USA Nation's Edge Choice card for a Titanium card with a fixed APR of just 8.9% for the rest of my living days! I don't really want to switch cards -- your service has been great. But I've noticed that the interest rate you're offering me has crept up to 43.9% in the past year. I'm going to have to transfer my balance unless you can lower the interest rate."

Them: (The sound of typewriter keys tapping and your credit and payment history being scrutinized.)

You: "Did I mention the free puppy they're giving away with each new account?"

Them: (The sound of fake typing as the operator tries to psych you out with silence.)

You: (The sound of you filling out the First Union Banc USA Nation's Edge Choice card application.) "I've already picked out a name for my puppy -- Poesy!"

Them: "Uncle! We'd like to keep you as a customer, so I am prepared to lower your interest rate and waive your annual fee, if you choose to stay with us."

At this point, they should offer you around 12% or even lower. If you get a dud operator who isn't feeling generous, ask to speak to a supervisor. Granted, if you're perpetually late with your payment, yell at dogs, or you litter, your lender may prefer to let you walk. So be prepared to follow through with First Union Banc USA Nation's Edge Choice. But if you have a solid track record with your card, you should have no problem negotiating a lower lending rate.

This tactic works best for those with decent credit ratings, a history with their current credit card company, a low unpaid balance compared to their credit limit, and no late payments in the past year. Still, even if you have a few blemishes on your record, it's clearly worth a try.

If they won't play ball -- even after a few minutes of you sobbing into the receiver -- it's time to move on. You might not be surprised to learn that there are offers galore out there. But again, read the rulebook before you tread into teaser-rate territory. For more guidance, read "Finding The One."

In matters of credit management, it nearly always pays to pull out all the stops and set your own rules.

These are the rules we expect all of our Motley Fool credit cardholders to live by. That's in part why we created our own card -- to help you stay on the right track.