I recently had someone ask me why I get multiple copies of the newspaper. When I started couponing again last October, I noticed fairly quickly that many of the good deals required you buy more than just 1 of the product, therefore requiring more than one copy of the coupon. Some deals even require that you have 3 or 4 copies of the coupon. Also, when things go on sale, having multiple copies of the coupon allows you to better stockpile items. I actually buy more than 1 type of Sunday paper as well. In my town, we have 2 different papers, and they each carry slightly different coupons, so I get at least one of each.
When I began to buy more than 1 newspaper, clipping coupons became a lot more work! Now, I have a new organizational system for my coupons that doesn't require I actually cut them out of the paper. I mainly use HotCouponWorld's coupon database searching system, which is pretty thorough; they even have links to printable coupons, such as Target store-specific coupons. I also download the list of coupons from Taylortown or another source and put them into a spreadsheet, so I have that for quick reference.
Buying one newspaper is a good start; you'll pretty quickly see that it pays for itself. Buying 2 or more papers, especially on coupon-packed weeks, can really jumpstart your couponing!