CLARKONOMICS: The Vehicle Affordability Index now shows that cars are the most affordable they've been since Jimmy Carter was president.

That's partly because of the intense competition in the car market that makes new vehicles a real deal at this point.

To arrive at this finding, researchers took the average income and figured out how many weeks you'd have to work to equal the average cost of a vehicle. The result? 23 weeks of work.

But here's the disturbing news: We're snatching defeat from the jaws of victory. First off, the average length of a loan is now 63 months, which is way too long. Second, repossessions have skyrocketed at all levels of car purchases -- partly because of the economic downturn.

42 months is the longest auto loan you should ever take out, according to Clark. If you can't afford the payment on a 42-month loan, then you need to buy a cheaper car. Paying cash upfront for a vehicle is always a good idea too.

Meanwhile, the price of used vehicles is down because there's too much supply. CarMax is among the major used-car sellers that's really taken it on the chin. So in addition to the great deals on new vehicles, there's never been a better time to buy a used car either. As always, remember to get a mechanic to carefully vet any used car before you actually buy it.

In related news, Clark recently read that an SUV purchased today will be worth a mere 30 cents on the dollar in 36 months. That's food for thought!

Over the last few weeks, we've received hundreds of calls from people who wonder whether they should ditch their old gas-guzzling SUV/truck and buy a newer fuel-efficient vehicle to save money.

Clark usually says that it doesn't make sense to do so. But that's just general advice without looking at the numbers.

If you want to get really granular, Smart Money has a new interactive tool that features 11 variable fields where you can enter your trade-in value, gas mileage, daily driving distance, etc. The tool calculates how long it takes to start getting payback.

You may not like the answer you get. Sometimes the only way to make it work is to buy a used gas-sipper. In this respect, cars from Hyundai and Kia tend to depreciate much quicker than those from Honda and Toyota.

And if you're stumped on your trade-in value, know that Edmunds, Kelley Blue Book and others haven't stayed current with SUV/truck values. So deduct about 25% from whatever they say.

The car market continues to take a beating, with the latest blow coming from a horrible sales month in June. Fitch Ratings, meanwhile, has downgraded Chrysler and GM -- citing weak sales and rising fuel costs, among other things.

Ford is also struggling with collapsed sales. The F1 Series is falling further down the list, and Ford is delaying a new remake because they can't sell the old ones.

In short, any automaker that has had a heavy emphasis on unloved giant trucks and SUVs is hurting right now.

So what's a Big 3 automaker to do? Well, in the case of GM, they're offering sweeping rebates and great buying opportunities. Look for 0% interest on a 6-year loan and possible additional cash rebates.

Clark doesn't even like 5-year loans…and here they're pushing 6-year ones!

But here's the bottom line: If you are in the market for a new SUV or pickup truck, there's never been a better moment to buy one. You're also likely to steal great deals if you're looking at used vehicles.

One caveat: As Clark has mentioned before, you should try to get it in writing that your Chrysler warranty will be honored no matter what.

The car business continues its downward spiral. New figures for March show that GM and Chrysler are down 20% and Ford is down 14%, year over year. Ready for the stunner? After defying slowdown, Toyota now is down 10%. Honda is the only of the Big 5 automakers that emerged flat but unscathed. Be on the lookout for deals!

One word about Chrylser, but Clark wants to preface this by saying he's hasn't heard or read anything to substantiate his beliefs, nor is he trying to kill business at Chrysler dealerships. He's just concerned because the company was recently taken private and is being run by non-automotive people. So should the company go belly-up, he fears the owners might just shrug their shoulders and move on to managing other assets in their handsomely diversified portfolio. Chrysler dealers might want to get assurances from corporate that warranties will be honored even if the company goes bust. Again, Clark has no inside knowledge about whether Chrysler is ailing or not. He's just thinking ahead about possible future scenarios.

Finally, if you like fancy cars, this is a good time. Porsche sales are down 26% and Lexus is down around 20%. The theory that the rich would continue buying status automobiles through the lean times has proven false. And keep in mind that cash is king at the dealerships as loans become harder to get.

Your car is the second most expensive purchase you're likely to make after your home. So people often ask about which vehicles hold their value best after 5 years. To answer that question, Kelley Blue Book has just released its 2008 Best Resale Value Awards tally. The winner is Volkswagen, which is making a comeback after some recent big losses. VWs keep just under half their value after a 60-month cycle. The other brands that round out the Top 10 are BMW, Acura, Honda, Porsche, Subaru, Lexus, Infiniti, Audi and Toyota. On the other end of the spectrum, the worst brand to hold value has been singled out as Suzuki. With Suzukis, you only get about a quarter back for every dollar after 5 years. Other cars that really stink when it comes to holding value include Kia, GMC, Mercury, Dodge, Chrysler, Lincoln, Jeep, Ford and Jaguar. On a related note, the Insurance Institute for Highway Safety (IIHS) says that the Subaru Impreza is the only small car that meets its strict safety standards. There were tons of midsized vehicles green-lighted by the IIHS, but not so in the large vehicle categories -- despite what you may remember from high-school physics!

Consumer Reports has released its annual vehicle reliability survey and Toyota has come out with a black eye. For the first time ever, the Japanese company's Camry has been dropped from the recommended list. Toyota made a corporate decision a few years back to become the world's largest automaker. In doing so, they had to take the focus away from making quality vehicles and shift it to growth. That explains why Toyota as a whole now checks in at No. 5 on Consumer Reports' tally of the most reliable vehicles sold in the United States. Ford has emerged as an unlikely hero in the report thanks to its enormous jump in quality. The "Not your Father's Ford" tagline is taking on a new meaning and people can no longer joke that Ford stands for "fix or repair daily." The top carmaker remains Honda, followed by Acura and Scion. The first American nameplate on the list is Buick, followed by Mercury and then Ford. The least reliable car sold in the United States is Land Rover, followed by Hummer, Cadillac and Mercedes.

Cars speak to us emotionally. Clark's producer Joel bought a 2000 Nissan Altima recently that doesn't really stir his emotions; he simply views it as dependable transportation. Joel might have picked a Honda Element if he were buying on emotion alone. Christa, Clark's executive producer, has named the hybrid version of her standard Lexus RX 300 as her dream car. Sometimes it's hard to step back from the emotional side and make a smart auto purchase. But think about the underlying hassle that comes with purchasing an unreliable vehicle. When you're ready to go car shopping, get pre-qualified for a car loan from a credit union and then get Consumer Reports' annual auto buying guide. Try to find a balance of quality and that emotional X factor and you'll be on your way to a great car purchase.

The market for gas-guzzling vehicles is awful! Car companies like Chrysler and GM are trying 0% financing with rebates to try and pull consumers back in. You can get incentives on some vehicles, others will give you 0% financing, and some deals will give you both! Each company has a “summer drive,” so that they will advertise better deals for SUVs and trucks to make up for their high gas consumption. However, if you're thinking of buying an SUV but don't plan to own it for the life of the car, keep in mind that it is very tough right now to get rid of a used SUV. Practicality is now beating out style.

There is a lawsuit pending against Ford Motor Company, which alleges that the company has been overcharging and cheating black customers at certain Ford, Jaguar, Mazda and Land Rover dealerships. There are always undisclosed mark-ups in the loans dealers give you when you do financing at the dealership. It’s typically about 2 to 2.5 percent higher than the offer they get from the actual lender. But Vanderbilt University found that black customers were charged $862 more for a loan, while white customers had only a $475 mark-up. Vanderbilt also found that blacks were uncharged two-thirds of the time, while whites were charged more one-fourth of the time. Ford claims that it had no idea this was going on. But it did happen. Avoid mark-ups all together by financing with your bank or credit union instead of the dealership. You can’t get taken if you don’t do business with these people. If you think the car dealership can beat the offer you get from your credit union, offer it up. Maybe the dealership can beat it. But make sure you have an offer when you go in. Never conduct business the other way around.

Clark thinks the car business is cleaner than it used to be, and there are actually decent people selling cars these days. But there are still some dirty players out there, and unsuspecting customers get taken all the time. There is a lot of emotional investment in buying a car, and many people are walking in blind with an inferior position. Clark recently heard a story from a former car salesman that was so unbelievable Clark thought it was a joke. The man said that once a week all of the salesmen and saleswomen get together at a bar for happy hour to vote for the person who ripped off a customer the most. That person was rewarded by having everyone else pay for his or her dinner and drinks. Christa overheard two men discussing the same accomplishment recently while she was out having dinner with her family. There will always be dirty car salesman. So, make sure you do your research before you buy. Check out kbb.com and Edmunds.com for car prices before you buy. Making the purchase of a car a true study before you buy is the key.