At Target, buy three select Seventh Generation or Mrs. Meyer's detergents and get a fourth item for free. (Add four items to cart to see this discount.) Plus, in-cart, you'll receive an extra 25% off. Even better, subscribe to take an extra 5% off and bag free shipping. Deal ends April 23.

A best bet is four Seventh Generation Ultra Power Plus Free & Clear 95-oz. Laundry Detergent for $23.73 with free shipping after the above discounts. That's $33 under the lowest total price we could find for this quantity elsewhere. Each container lasts for a purported 54 loads.