These are the actual coupon vendors for manufacturers.  Coupons are up-to-date and change periodically.

www.coolsavings.com

www.coupons.com

http://www.couponsinc.com/corp/source/cp_clientlist.asp

www.redplum.com

www.smartsource.com

Here's a site where you can save the coupons you choose to your grocery store savings card (select grocery stores) to redeem at checkout by swiping your card:

http://www.cellfire.com:80/affiliate/fullpage.php?cf_tlc=cml