Can you use a digital or eCoupon with a paper (insert or printable) coupon?
In most cases, the answer is NO. In Arizona, Fry's will give you back your paper coupon if you have already loaded a coupon for the same product. It doesn't matter if your paper coupon is worth more.
SavingStar & Upromise do not give you the savings instantly. You are accumulating future savings. Currently, there are no systems in place at the register to stop you from loading a coupon for future savings and redeeming a paper coupon at the same time, but they don't want you to do it. SavingStar's official statement is . . .
SavingStar eCoupons will work whether or not you combine them with other services' coupons, but they are not intended to be used this way. Generally, manufacturers state that it is against their policies for shoppers to redeem more than one manufacturer's coupon for the same purchase. Using in-store coupons in combination with SavingStar eCoupons is not a problem. In the future, we may implement mechanisms to limit the combination of SavingStar eCoupons with other manufacturer coupons.
In all honesty, I load my future savings coupons ahead of time, so there are times when I also have a paper coupon. I don't intend to combine, but I use this program as a "load & forget" thing. I consider the savings a nice bonus, but it's not what makes me decide to purchase an item. If you're more organized, you can make sure you don't combine them. The system may change in the future, which would probably mean I will abandon this method of savings since I would prefer the instant, guaranteed savings.