How do you keep all your coupons organized?

I'm a cashier, so I've seen it all. I have customers come in with binders of coupons that have the plastic sheets that you use for baseball cards with coupons in each slot. One page is for frozen food. Another for household cleaners. Household items. Dairy. Then food. They also bring in scissors and a calculator. Although it may be bulky, it does seem to work better then using a recipe box or an expanding folder. With the binder idea you can see the coupons and everything. I have tried the recipe box/expanding folder with coupons and it doesn't seem to work. It works if you have a few coupons, but if you have a lot, I would go with the binder. Just place it laying flat open so it covers the seat of the cart and it's flat, not at an angle.

i use a coupon wallet and organize by dates