I don't use them a lot, but I try. I do know that what they do on that show isn't always allowed. If you look, some of them say "Only X number Per order." I try to use them when things are on sale so you get more bang for your buck. I also only try to buy stuff that I use. Although in a lot of cases, Costco is just as cheap without all the headaches
PS: That show kinda freaks me out. Seriously, who needs a Wall-of-Toothpaste? They also buy a lot of junk food/packaged junk and very little actual vegetables. The work they put into all that is astonishing too!