I am personally a directbuy member and I find it saves me quite a bit of money. It all depends what you are buying. We just purchased an old house, so buying tiles and things like that through directbuy saves us a lot of money for our renovations, and we have saved our membership fees within a year of being a member. Also, I feel most of the posts above about directbuy are from one dis-satisfied customer. If you notice, most of the posts are posted by someone with very poor grammar skills and uses the word 'there' for 'their'.
Name me one product that you can find for cheap and I will tell you what price I can get it for at directbuy.
I will say that they use some pretty strange tactics for trying to get you to sign up. However, we were able to sucker them into letting us wait a year before signing up. It's all sales at the beginning, but you really do save when you're purchasing a lot of large items.