Tee, there are many ways to obtain previous Sunday paper coupons:
You can purchase coupons at a very low price at eBay. Many people trad there coupons, usually at lots of 10, 15, 20 or more. See Coupon Trading for more information.
You can use Coupon Clipping Services. You simply go online, choose the coupons you need and find them in your mail box a week later, all for a negligible fee. I admit that I don’t use them myself, but from what I hear they’re pretty good. Click here for a list of such services.
You can exchange coupons with other people. Many forums specialize in coupon exchanging.