Like Companies on Facebook
Everyone is on Facebook these days including your favorite brands. Like their fan page, and you could be rewarded with free product coupons (either at sign up or in the future).
Companies that Like to Show the Facebook-Freebie Love:
Tip: Set up a Google Alert for the phrase "Facebook freebie," and you'll be among the first to know when a new deal goes live.
Get serious about rebating. It's a great way to earn both rebate checks and free product coupons.
Contact ManufacturersMake a list of the products that you use regularly (food, cleaners, toiletries, etc.). Then, email the manufacturer of each one to let them know what you think of their product good or bad. A bit of feedback could (and likely will) net you a mailbox full of coupons for freebies.
Sign Up for Product Tests
Agree to test products for companies, and they'll hook you up with plenty of loot (free product coupons included).
A Couple Test Sites to Sign Up For: