These are a collection of coupons sites (many have free samples too). Some you may need to register at:

All You Magazine Printables

A& P Coupons

Couponbug

Couponizer

Couponmom

The Coupon Loop

Coupons.com

CouponSurfer

Delicious Living

Earth Fare Healthy Savings Coupons

Eat Better America

EcoCoupons

Ever Save

Grocery Smarts

Health-e Savers

Healthy Living Coupons

Mambo Sprouts

Mindful Mama Coupons

Redplum – print online coupons

Shortcuts

SmartSource – print online coupons

Upromise – Automatically load grocery coupons onto your frequent shopper card at a variety of stores. A powerful tool for saving for college or paying on any student loan.

Vocalpoint – they send samples to you in the mail as well as coupons.

Whole Foods Printables

Wow Coupons

GROCERY STORES
Register your Kroger Plus Card and load coupons onto it:
Kroger
Register at Meijer Mealbox at:
Meijer