The Sunday paper isn't the only place to find coupons for the things you buy.
*Check out online coupon clipping services - services like couponclippers.com charge a small fee for handling and sorting of the coupons. It can be valuable for coupons you would use a lot of.
*Coupon Databases - There are some websites that dedicate themselves to keeping lists and links to coupons all over the web that are printable. Hot Coupon World has a good database. My personal favorite is the A Full Cup database.
*Ebay - Believe it or not, there are lots of coupons to be found on eBay. You can buy some coupons in bulk (like if you want Barilla pasta coupons, you can buy a stack of 10-20 of them for about $1), you can also buy auction lots of random coupons that have been clipped from newspapers. Most of the time, these lots do cost a couple of dollars, depending on how many coupons you are looking for but you make up the initial cost in savings at the grocery store checkout line.
*Manufacturer's websites - Often you can find coupons somewhere on the product website. Most of the time, these are unadvertised, so if you want them you have to go and look for them. It can take a little digging and footwork, but sometimes the websites have higher value coupons, which are worth a little extra effort.
*Printable Coupon Sites - The most well known resource are websites like coupons.com. Similarly, there is also smartsource.com and save.redplum.com where you can print out coupons, similar to those you would find in the Sunday Circulars. Most of the time, you can print these coupons twice for double the savings.
As always with printed coupons, you might want to check with your store management before you get into line about their policy on internet coupons. These days, most stores will take them (despite what the cashier says), but there are stores that will either limit the amount you can use, or say they don't accept them at all. Most grocery chains do have their coupon policy on their website; sometimes it's in their FAQ section, or in a link of it's own. If a cashier tries to go against the store coupon policy by saying you can't use them, remain calm and polite and inform them of what you were told by management. Many times, in this instance, being nice will get you further than snapping back at the cashier.