We have had a Costco membership for years now, but my husband runs his own business and buys a great deal of his supplies from there. We buy a lot of our bulk household products there - toilet rolls, kitchen roll, washing powder, etc - and definitely see big savings on those. You can definitely save money, but bear in mind that you do usually have to buy in bulk so you need to have somewhere to store everything. We buy big blocks of cheese too, and their meat is usually very good quality, but again, you need space to keep it. It can be easy to get carried away and buy things you don't really need as well - although not if you're with my OH, as he just marches straight to what he wants, no browsing around when you're with him!