Prices on Amazon oscillate week to week far more than you might think. Paste an Amazon url into Camelcamelcamel.com to see the chart of an item’s price history. If you are not in a hurry, you can use the chart to set a plausible low target price and Camel will send you an alert and buy button when (if) it reaches that price. — KK

Before buying something on Amazon enter the URL for the product at fakespot.com. This free service will analyze how many shill reviewers have rated a product, and award a “Fakespot Grade” from A to F. A low grade doesn’t necessarily mean a product is bad, it just means you shouldn’t take the reviews and user ratings into consideration when making your decision to buy something. — MF