Amazon, eBay and Craigslist are the frugal trinity of the online shopping revolution: Between them, you can find virtually anything you're looking for at a good price. But if you're just using each website as is, you're not getting the most out of the experience, and you might be overpaying.
A cottage industry has sprung up around the major e-commerce sites, with various third parties finding ways to improve the shopping experience, fill in the gaps and exploit inefficiencies. Taking advantage of them can help you find products you'd otherwise miss and save a decent chunk of money. Here are a few to check out.
Matt Brownell is the consumer and retail reporter for DailyFinance. You can reach him at Matt.Brownell@teamaol.com, and follow him on Twitter at @Brownellorama.