Here are a list of links to the most popular and widely used coupon sites:
smartsource.com
coupons.com
redplum.com
http://www.grocerycoupons.com/joinnow.asp
cellfire grocery coupons
We will be adding more as we come across those that do not duplicate the savings above.
Here is a great site that links approximate Walmart prices for items that have current coupons in circulation, so that you can match the coupon with the Walmart sale price to look at your savings. A number of items would be free. Most of the links to the coupons are provided.
http://www.grocerysmarts.com/indexnational.php?walmartnat
