Get automatic savings delivered to your doorstep: Amazon's Subscribe & Save program is a combination of convenience and savings. Simply select items you buy regularly -- anything from diapers to paper towels to office supplies -- and Amazon will deliver them automatically AND give you 15% off. You choose how often the item is delivered (anywhere from monthly to every six months) and you can change or cancel deliveries any time. The caveat? Some items, like diapers, are generally a great deal, while others are on par with your local grocery store, so do a little comparison shopping first.
Click for golden deals: See that gold treasure chest at the top of the Amazon home page? Make it your first click for some of the best deals around. Every day, Amazon features a Gold Box Deal, several Lightning Deals, personalized discounts, and more. The Gold Box and Lightning Deals can be huge, especially when it comes to electronics. (I recently landed a printer for 50% off.) The savings on personalized deals aren't as impressive -- my offers today included a DVD for $0.50 less than the regular price and a video game for $1.85 off. Still, because these items are selected based on your purchase history, you can save a bit on something you'd buy anyway.
Protect yourself from price swings: It's a little-known secret that Amazon prices change frequently, in some cases daily. The best way to play the price swings? Add items to your shopping cart in the "save for later" section and check back often. A yellow box at the top of the page will alert you to any price changes. It requires a little patience, but I've scored deals of up to 50% off using this strategy. Price drops from the Gold Box and Lightning Deals don't show up on the Shopping Cart page, so you'll still want to click the Gold Box icon for those.
Score cheap reads: If you like free books, you'll want to bookmark Pixel of Ink or sign up for the site's email newsletter. You'll get notified of the best deals on Amazon's Kindle e-books -- most are $2 or less, and many are free. These aren't just dusty old classics, either. Thanks to Pixel, I've got a virtual bookstore stocked with best-sellers, cookbooks, how-to guides, and kids' books, all downloaded for free. Best of all, you don't even need a Kindle: A free app allows anyone with a PC, Mac, iPad, or iPhone to read Kindle books.
Scout the bargain basement: Full of refurbished and open-box items, Amazon's Warehouse (warehousedeals.com) is a great source of discounts on nearly everything Amazon sells, from Kindles to candles. As with any discount site, it helps to know the going prices for the items you covet: A deal on the P90X fitness system offered 30% off, while the discount on an Apple TV was just a few bucks under retail. Worried about defective merchandise? All Warehouse purchases are covered by Amazon's standard 30-day return policy.
Hit the virtual outlet mall: Amazon's Outlet doesn't offer as many deep discounts as the Warehouse, but the prices are still better than retail and the selection is much wider. You can find the Outlet link by clicking that trusty treasure chest and looking right under the search box.
Snag free shipping on everything: Prime is a decent deal, but it's even better when you get it for free. Amazon offers two programs that let you do just that. If you have a .edu email address, Amazon Student gives you a free year of Prime. Don't qualify? Try "Amazon Mom." You don't have to be a mom, or even a parent, to qualify. You'll get three months of Prime for free, 30% off on diapers, and you earn an additional month free for every $25 you spend on qualifying items (up to a year). Here's the quirk: While most of the qualifying items are kid-related, not all are. Just look for the "Amazon Mom" banner on the product page. I've found it on a seemingly random assortment of furniture, electronics, and household items. (Note: Neither of these programs includes free instant video.)
Sign up for tailor-made savings: Amazon helpfully offers dozens of email subscriptions -- select the categories you most often shop to be notified of special deals and discounts. My favorite is the "New Deals at Least 50% Off" (find it under the Outlet category).
Charge ahead!: Only for the most die-hard Amazonian, the Amazon Visa card is a good way to compound your Amazon savings, IF you commit to paying it off every month. You'll get a $40 credit when you sign up, plus three points for every dollar spent at Amazon, redeemable for -- you guessed it -- Amazon gift certificates.
Motley Fool writer Robyn Gearey does not own shares of Amazon, but she sure wishes she had taken all the money she's given it over the past 12 years and bought the stock instead. Motley Fool newsletter services have recommended buying shares of Amazon.com.