Paying retail price is for people with poor impulse control. If you can delay your gratification for the shiny new toy you want and maybe do a little research first, you can almost always get what you're looking for at a price much lower than what you see either on store shelves or at the first online retailer you go to.
This should not be news to you, of course. If you're a savvy CNET reader, you're already accustomed to researching before you buy. Perhaps you scour Rick Broida's Cheapskate blog to stay abreast of good tech deals. But when you're looking for a price on a particular item, there are dozens of sites and services that can save you money. You just have to remember to use one of them. Here are my picks.
The necessary reminder
InvisibleHand isn't always the best deal-finding site, but I highly recommend installing this browser add-on since it reminds you when there are better deals online than the one you're looking at. Unlike the other sites I recommend, you don't even have to remember to use it.
The InvisibleHand extension stays out of your way (invisible) until it sees a product on a site it's familiar with (like Google or Amazon). Then it pops down a little advice bar telling you if you're looking at the best real-time online price for the product that it knows of, or if there are less expensive offers online elsewhere. Very nice.
It has limitations: it doesn't calculate shipping costs, or taxes, or coupon discounts (yet). But it's still very valuable. Even if you don't use its recommendations, the fact that waves at you when you could be saving money makes it worth the download.
The old standards
Nextag has been around for years, and I still use it as my go-to-site for comparison shopping. It pulls data from a healthy selection of sites (including, competitors claim, some gray-market resellers), and calculates price as delivered including tax and shipping. Nextag is far from the only player in this space. Google Products is not a bad solution either. It works like Nextag but with a different selection of sources, so it will sometimes find different prices. Also be sure to check out Microsoft's Bing Shopping, which will show you cash-back offers on some products, which sometimes will save you money over other product search engines.
For commodity products (cables, hard drives, and so on), check out Pricewatch, which gives you an extremely basic but fast and useful list of prices for popular parts from many vendors. Unfortunately it doesn't scan Monoprice, which has the best prices outside of eBay for cables and other tech infrastructure products.
The mobile tools
When you see something you like in a real, physical store, stop. Whip out your iPhone and fire up the RedLaser app (99 cents). It's one of several available consumer-goods barcode scanner apps, in my opinion the best. It'll find the item you're looking for and what it's selling for online, as well as try to find it in other brick-and-mortar stores nearby (with mixed results). Bonuses: when you scan a book, it'll find it in a library; when you scan food items, it'll list allergens in it. It's also got the best UPC entry keypad for when the barcode scanner doesn't work, which is often if you're using an iPhone model other than the 3GS.
The coupon site
The Web is awash in coupon deals on various products. And like the price-checking tools, there are several good sites that will help you find these deals. I currently recommend RetailMeNot. It has a healthy collection of coupon codes from around the Web and a good community of users that rate each code as usable or not.
FatWallet is also worth a look. It has community feedback on low-price deals as well as on coupons, and if you join the service you can earn cash-back awards from various retailers.
The most interesting price-finding site, to me, is Bountii. It combines standard pricing data (which it gets from data feeds, like other price-comparison sites) with the low prices on items you can only get when you add an item to your shopping cart. (It has more cart-only prices than InvisibleHand, but it's worth noting that its prices are not real-time, as InvisibleHand's are.) It also calculates the cash-back prices you might get on an item if you buy through Bing, or FatWallet, or through various credit cards with rewards programs. If you join the site's community and find a new low price on an item for which there is a "Price Hunt" on, you get both cash rewards (a few bucks, paid to you instantly via PayPal) and points which may be redeemable for some other benefits later.
Bountii does the best job of cutting through the clutter of the multiple conflicting offers a store might have on a single item. Note that Bountii only displays results from stores that are manufacturer-authorized to sell the products listed, so it may not show you the lowest prices from stores you've never heard of, but everything you'll see will be legit.
The old-fashion way
When in doubt, call the store. For many tech products (and especially for service-based products like wireless or content subscriptions), you may be able to get a substantially lower price if you simply ask a sales rep if they have current deals or promotions, or just if they're willing to cut you a deal to make a sale. Remember, it's their job to sell, not have you go somewhere else. Or look at it this way: by giving the sales rep a chance to make you a deal, you're not only saving money, you're helping them do their job. Everybody wins.