How can I coupon to get stuff for free or almost free?

If you've ever seen the show Extreme Couponing on TLC, you know what I'm talking about. I want to coupon to buy food or toiletries for the local food pantry. I also want to buy Gatorade and sell it along with lemonade or something at a lemonade stand. I'm only 13, so I can't get a store rewards card and don't have a credit card or anything like that. Thanks!