Students with a valid .edu e-email address can sign up for the Amazon Student program. This means a 6-month free trial of Amazon Prime, and only $39 per year for Prime after that. If you're not a student and you want a free .edu e-mail address for some unrelated reason, Digital Bridge has a list of sites that give them out for free. (Wink.)
Refer a friend to Soap.com, and they'll get a 20% off promo code for their first order. Unfortunately, the discount does not apply past $100 spent. In addition to their discount, you'll get a $5 gift reward that you can keep or donate to charity.
The homepage offers random, monthly promotions like Mrs. Field's treats when you buy certain items.
New deals start every Sunday, and typically last one week. The Deal of the Day changes daily, as you might guess. It offers 25% or more off select products, plus free shipping.
If you refer a friend to VitaCost you can get $10 off your next purchase over $30. Your friend will also get a coupon for $10 off their first purchase over $30.