Sign up with General Mills' Psssst community to receive test products and coupons for products to try. They also usually send high value coupons for you to share with others.
My most recent mailing from them contained a coupon for a FREE Green Giant for One frozen vegetable and 10 $1.00 off coupons to share :)
About 2 weeks ago I received a full-sized box of Chocolate Cherrios and coupons for $1.25 off to share with family and friends! (These are VERY good btw!!)
Again, you do not receive a lot of e-mail from them which is nice :)