The trick, of course, is keeping tabs on items you want to buy and finding out when they go on sale again. Sure, you can subscribe to newsletters, which the stores love, but those won't pinpoint specific items you want -- and eventually the deluge of mail gets to be too much.
Instead, put a price-tracker to work. These tools monitor specific items and notify you when they go on sale. Here are a few worth checking out:
Available for Chrome, Firefox and Safari, the Camelizer leverages the popular (but curiously named) Camelcamelcamel price-tracking service for Amazon. Once the browser add-on is installed, just head to any product page and then click the Camelizer button. You'll see visual price-history data, which will tell you the lowest the price has been during the past year. And with one click you can track that product and get notified of price drops.
Another Amazon-only tool, this one for Chrome, Firefox and Opera, Keepa works a little differently: It embeds price-tracking data right into the Amazon product page. (You have to scroll down a bit to see it, otherwise you might not even realize Keepa is working.)
When you click the Track Product tab, you'll see a desired-price slider -- meaning the price has to drop below a certain threshold before Keepa triggers a notification. And those notifications can come via email, Facebook, Twitter or even RSS.
Compatible only with Chrome, this offshoot of shopping assistant Slice makes it a snap to track prices -- not just at Amazon, but also at stores such as Best Buy, Target and Walmart. A simple "watch list" shows you at a glance the items you've tracked, and one click removes them from your list. It's about as basic as price-trackers come, but good if you want to extend your reach beyond Amazon.
Have you found a price-tracking tool you like better? Name it in the comments!