Like most people, I have a past littered with expensive mistakes. I won't bore you with the list, but it includes sports cars, redheads and computers.

I'm not qualified to help you with automotive or redhead woes. But I can help you avoid some really dumb mistakes when it comes to buying gadgets and computers.

I was reminded of all that this morning, when I answered a question in another column I write in which I deal with reader questions. Someone wrote to tell me they spent $630 on an extended warranty for a laptop.

Since I just answered that question, I won't dwell on extended warranties other than to tell you that they're almost always an expensive mistake. In cases like that --- where someone paid more than half the value of the machine for a warranty --- they're downright rip-offs.

That's just one way to waste your money. There are others. And so you won't think I'm being sanctimonious here, let me assure you that I've made every mistake in the book at one time or another:

> Buying gray market goods. You can find some great deals online and advertised in print, especially with gadgets such as digital cameras and high-priced video equipment. You'll often see prices quoted that are way below what you'd ordinarily pay.

That can be a tip-off that the company is selling a gray market product. Unlike black market goods, these deals are not illegal or even unethical, especially when the product is advertised as gray market. It just means that the dealer is selling a gadget that was intended for another country.

Here's the rub: Most manufacturers will not honor the warranty for gray market goods. If you're in doubt whether the item has a U.S. warranty, check with the manufacturer to find out whether the retailer is on the authorized dealer list. The ugly truth here is that some retailers will lie if asked whether the item has a U.S. warranty.

> Being one of the elite. Whether it's a computer, camera or sound system, you can waste a huge amount of money buying equipment that is on the leading edge of technology. The very fastest computers, the most sophisticated digital cameras, are overpriced.

When a product first hits the market, manufacturers try to recover the research and development costs within the first year.

So avoid the very cheapest gadgets and the most expensive ones. Buy those priced in the middle of the pack unless you have a specific need for leading-edge technology.

Another common mistake is taking advantage of add-on deals for accessories. That's a way stores often take advantage of you. For instance, when I bought my high-definition television, the salesman tried really hard to add on a DVD system (despite the fact that I already owned one); a sound system; expensive cables to connect everything; and the extended warranty.

Walk into the store knowing what you really need. Do some research to find out the fair price for any accessories that are on that list.

It's easy to get swept away by a sales pitch. You are, after all, already spending a lot of money, so the temptation is to think, "Well, what's a couple of hundred dollars more." But it may be $200 or so that you don't need to spend.

> Going for extended payment plans. Both computer and home entertainment dealers often offer two- and even three-year payment plans with no interest.

But if you miss a payment for any reason, interest payments kick in. Even if you've paid most of the balance, those interest payments will apply to the entire amount you financed. And the rates charged are often downright criminal.

Some people can handle these no-interest deals and faithfully pay without missing a deadline. Be sure you are one before signing on the dotted line.

Also be aware that long-term no-interest loans can entice you into spending more money than you can afford. If you can't afford to spend several thousand dollars today, there's a good chance that you won't be able to afford it tomorrow.

Like I said at the beginning, I've been there myself. So think of this as a chance to learn from my expensive mistakes.

tecbud@ajc.com