You have probably heard that you can’t stack manufacturers coupons, meaning if you have two manufacturer coupons you’ve clipped from an insert, even if they are two different coupons (say, one 75 cents off and the next $1 off). So people think they can’t combine any coupons and all, and if you believe that, you are saving even less money than you could.
The way to do this is to stack manufacturer with store-specific coupons. Sometimes you get them when you pay at the cashiers, other times they are printed in weekly flyers or local newspaper ads. So you might have $1 off with a store coupon and an additional $0.75 off with a manufacturer coupon, meaning you now have coupons worth $1.75.
Most stores will also double store coupons as well as manufacturers coupons (check with the individual store if you are unsure) so when you stack coupons you can often get products for free or nearly nothing.