Couponing can be a very simple or complicated process.  It depends upon how much time you are willing to invest in order to get maximum savings.  Here is a list of coupon sites that you can print coupons (maximum 2 coupons per computer).  You will need to download each sites coupon printer in order to print the coupons.

Coupon Insert Schedules
Redplum 2012
Smartsource 2011
Blinkie 2011

Main Coupon Websites
Coupon Network
P&G Everyday Solutions

Coupon Policies
Bi-Lo's Coupon Policy
CVS's unofficial Coupon Policy found on Southern Savers
Food Lion's Coupon Policy
Harris Teeter's Coupon Policy
Ingles' Coupon Policy
Lowe's Foods Coupon Policy
Rite Aid's Coupon Policy
Save-A-Lot's Coupon Policy - Save-A-Lot honors manufacturer coupons for national brand items carried in our stores. Coupons should be used by the expiration date listed.
Target Coupon Policy
Walgreens' Coupon Policy
Walmart Coupon Policy

Other Coupon Sources
Blinkies - coupon dispenser usually attached to a shelf near the product
Catalina - coupon dispenser usually located at the store registers
Hang Tags - coupons hanging on a product
Peelie - coupon is attached to the product and you can peel it off and use it at check out
Register Tape - coupons printed at the bottom or back of your receipt
Tear Pad - coupons usually attached to a shelf near the product or a board in a section in the store

CVS has Extra Care Bucks (ECBs)
Rite Aid has UP Rewards, which print out at check out (Register Tape)
Walgreens has Register Rewards (RRs), which print out at check out (Catalina)

In addition to the coupon sources mentioned above, you can find many paper coupons printed on the inside of product packaging.  While getting your Sunday paper coupon inserts, don't forget to look at the Parade or any other magazine insert, I have found coupons printed in them as well.

Speaking of Sunday papers, I subscribe to two of my local papers.  I do this in order to get multiple coupons and the coupons vary so much from paper to paper and even from Region to Region.  You can find a list of Sunday paper inserts on the Resources page.  Sometimes there are no inserts while other times there are five!  You can also preview a list of coupons that will be in the Sunday paper by knowing where to look in forums or on couponing blogs and websites.