Shutterstock You will need to exercise some self-restraint.
In "Rock Breaks Scissors: A Practical Guide to Outguessing and Outwitting Almost Everybody," William Poundstone explains how to trick websites into offering you discounts using a method he calls the "abandoned shopping cart ploy."
It's simple: Fill up your cart on any retail site and start the checkout process, partially filling out your shipping information and email address - but no payment information. Then exit the site and wait.
Much of the time, retailers will email you a reminder about your abandoned cart, usually including a discount coupon or free shipping.
Why does this work? According to Poundstone, 65% of all online carts end up abandoned, so retailers send follow-up emails in an attempt to close the deal. "Some companies are willing to discount their profit to gain a new customer, knowing that repeat customers might not care so much about price," he writes.
Poundstone likens the practice to walking away from a car salesman - it forces him to put the best deal on the table.
The shopping cart ploy might not be a foolproof method, but it's certainly worth a shot.