You can ask family and friends for their coupon inserts if they are not planning on using them. Some people order them on line.

Is there a local Saturday paper that includes either the SmartSource or Red Plum inserts?  If so, those papers are usually less than the cost of a Sunday paper.  Some of us are also lucky enough to have local free papers that include the SmartSource. 

I also purchase several copies of the Sunday paper.  I include them in my transactions at CVS, Walgreens and Rite Aid.  I get to offset the cost of them by using the store's reward money (UPS, ECB's and RR's) to pay for them.

If your grocery store only doubles up to 5 coupons, you may want to consider doing small transactions.  Make your purchase, put your groceries in the car and come back in again.  Does your store limit the amount of $1 coupons (I'm assuming they don't double those)?  If not, you can include those items in with your first transaction and only have to do 2nd or 3rd purchases for your coupons under $1 that will double.

The stores that I have more success at stacking coupons (store issued + mfg issued coupons) are stores like CVS, Walgreens and Rite Aid. 

Do you have a Target near you?  They have many coupons on their website (food, health & beauty, etc.) that you can print and those can be stacked with a mfg coupon. 

Walmart gives the overage on coupons so you can put that towards the cost of other items you are purchasing.  For example if you have a $2 off coupon and the price of the item is $1.79, you will get the $.21 overage.

Lastly, a $6 off nwp wine tag is a 'tag style' coupon found hanging on a bottle of wine for $6 off the specified item and the nwp mean no wine purchase required.  I've yet to score any of those great coupons and my blue eyes are turning green with envy from Kathy and Cardinal's awesome shopping trips yesterday!

Hope this has helped you.  Ask any questions and check out the store forums for what stores are in your area.  I have had to rethink the way I shop and open myself up to buying brands I wouldn't normally buy but have been very happy to do so and save lots of money! Oh, and if you haven't purchased Kathy's book, "How to Shop for Free" you definitely should!