Washington  - Buy a cell phone, smartphone, or PDA today, and you'll quickly find that there is a plethora of products available that promise to make your experience with your handheld device better.

Some of these products are helpful, some are unnecessary, and some are downright indispensable. All of them, however, can be costly, especially if you're not careful about where you hand over your cash. So how can you separate the good deals from the bad? Read on for some guidelines.

--- Cables and chargers

Virtually all handheld devices come with a charger and a cable so that you can hook up your device to your PC. Veteran handheld users knows that one charger and cable, though, are often not enough. You need a car charger for when you're on the road, and you probably want or need additional chargers and cables for work or other locations in which you normally have your handheld device.

Cell phone or wireless stores love this dilemma, of course, because they typically have a range of pricy chargers and cables ready to sell you. What they won't tell you is that you can often buy compatible chargers and cables for a lot less money from an online parts vendor such as Amazon or Newegg. com.

Take the example of the USB-to-micro-USB cable that a BlackBerry Curve owner needs in order to hook the device up to a PC. You can find these online for just a couple of dollars, but you might pay up to 10 times that amount if you purchase the cable from a wireless store. The same goes for car chargers. Shop around online - or even on eBay for used parts - and you'll likely come away with all of the extra chargers and cables you need for a fraction of what you'd pay for them at your cell phone dealer.

--- Memory

The majority of today's cell phones and smartphones also include digital camera, video, mp3 playing, and voice recording capabilities. And that means there's never enough storage space for all of those media files.

You can buy additional memory cards for most handhelds, but again, if you look in the wireless store for those, you'll pay more than you have to. Instead, find out the type of memory that your phone accepts - many today require microSD memory - and purchase it from a reasonably-priced online retailer. Instructions for inserting the new memory are usually included in the manual that came with your handheld device.

Shop around a bit, and you'll quickly find that adding lots of extra memory won't break the bank, either. The best price-to-capacity bargains today are with microSD cards of 8 gigabytes (GB). Larger cards exist - 32 GB is currently the maximum capacity for the tiny microSD cards, although 64 GB models are on the way. But the price jump from 8 GB to 16 GB is more than double. Expect to pay about 20 dollars for an 8 GB card and a bit more than double that for a 16 GB model. Be sure your handheld device will recognise the capacity that you wish to use.

--- Screen protectors

The screens on today's cell phones and smartphones seem to get bigger by the day. Indeed, devices such the iPhone and BlackBerry Storm are pretty much all screen, at least on one side. It's natural for new owners of such devices to want to protect those sparkling LCD screens with some type of clear film, and plenty of manufacturers have heeded the call and offer screen protectors of all sizes. Zagg's Invisible Shield (http://www.zagg.com) is one that's frequently cited for its quality.

Yet most of today's handheld devices come equipped with screens that are remarkably scratch and dent resistant. Log on to YouTube, and you can easily find videos of people who have gone to great lengths to prove this - attempting to scratch their iPhone or BlackBerry, for example, with a nail or knife, only to fail.

So you can probably forego the screen protectors - unless you want to use one for the back of the device. Owners frequently express dismay that the plastic backs of their handhelds are prone to scratches and fingerprints. If that bothers you, a screen protector may be the answer.

--- Headsets

If you talk on the phone a lot - or you need to talk hands-free in the car - chances are you've looked at the Bluetooth headset or ear pieces that make this possible. The advice here is the same as it is with shopping for cables, chargers, or extra memory: shop around. Dozens of companies make Bluetooth headsets that are probably compatible with your handheld device. You'll pay a lot less by buying online than you will if you purchase the headset from your cell phone dealer.

--- Disinfectant wipes

You probably wash your hands regularly to avoid picking up or spreading germs. But do you wash your mobile device? The fact is our cell phones, PDAs, and smartphones are germ magnets - in tests, they've proven to be competent carriers not just of cold and flu germs but of more dangerous hepatitis and staph viruses. One study even found a typical cell phone to be dirtier than a keyboard, toilet seat, or the bottom of your shoe.

How can you keep your cell phone as germ-free as possible without damaging the device with water? Perhaps the best accessory you can purchase are pre-moistened disinfectant wipes. They're available from many companies today and typically come in handy dispensers that you can keep at your office or home. If you choose instead to use a disinfectant spray to wipe the mobile device, be careful not to spray liquid directly onto the phone or device itself. Instead, spray the disinfectant onto a clean, lint-free rag or soft paper towel first, and then start wiping.

--- Insurance

Mobile devices fall victim to all sorts of mishaps - everything from being dropped onto concrete to being accidentally dunked in a cup of coffee. Your primary defense against such trouble is a good insurance policy.

But not all insurance policies are created equal, and in fact, the standard insurance policies sold at wireless stores - which typically involve a per-month fee in addition to your wireless rate - can be among the worst. Before you sign up for one, be sure to read the fine print. Many such policies do not cover the most common cause of cell phone death, for example: water damage. The fact is that even a small amount of water that makes it way inside of your cell phone can completely destroy it.

So whenever a salesperson in a wireless store attempts to sell you an insurance policy, ask specifically whether water damage is covered. Also ask him or her to detail not what type of damage is covered but what is not.

Also, know that handheld or cell phone insurance policies are available from more places than just the wireless store. For instance, the company that makes your handheld device may offer a more comprehensive insurance plan than the store from which you purchased the wireless device. Also, if you have homeowner or renter's insurance, the company from which you buy it may already cover your device without your knowing it. It's worth calling the insurer and asking specifically whether your phone or handheld is covered - and, if not, whether they offer insurance for handhelds. Most do. (dpa)