This Sunday's Coupon Preview is not up at http://www.sundaycouponpreview.com/. It has a list of the coupons you should find in this Sunday's paper. This weeks paper includes 1 Smart Source and 1 Red Plum. By seeing what's in the Inserts early you can start planning your trip, or see if you want a few extra papers.
You should look at either getting a Newspaper subscription from local paper or going to the Post Office or Gas Station/Convenience Store and buying one. I also recommend getting a National Paper that has the inserts. Why? Last week I purchased 4 papers, while the majority of the coupons were the same I did get a few different ones, some of I wish I had more of (Nozema Razor, Tabasco Sauce, Dove Soap, Etc.) Also different areas of the country have different coupon values. For example you might get a $1.00/2 in one area and a $0.50/1 in another and the $1.00 coupon doesn't double. Therefore the $0.50/1 is actually more like $1.00/1.
From what I read the number of Newspapers you should get is 1 per person in the household, I always buy 2 myself and the 4 papers were a little too much, I'm never going to buy 4 of some items. If you need more you can always order them from a Coupon Clipping Service, or Ebay.