Fred's Discount Store has double coupon day on Saturdays. I wasn't aware of this until one Saturday I used a coupon & noticed the cashier doubled it. I asked & found out that on Saturdays they double the coupons - even $ 1.00 coupons!
Editor's Note: We don't have these in our neck of the woods. Looks like a big chain in the south. Here's their site, it has a store locator: