I get asked this question all the time !! let me start by saying that I have never bought coupons ! I personally think it defeats the purpose.
What I do is :
Circulars- these are delivered twice a week in my town, most people don't pick them up, so I do.
Dumpster diving- This is when I hang out at the local recycle bins....I get 20 to 200 inserts per bin.
If you don't have these options, I would suggest that you ask all of your family, friends, neighbors and co-workers to save them for you. You will be amazed at how many you will aquire.
On Sunday alot of people read the Sunday papers at their favorite restaurants and leave them behind, this is a great source to.
The laundry mat...same as above.
This weekend is a great time to buy multiple papers, there will be 4 to 5 inserts and it will be a great way to stack up for the New Year.