I don't have a big family (reduced to just me my mom and my dad since my brother moved out) so shopping at Costco can be slightly perilous for us. Make sure that when and if you buy something there, you LIKE it, cause you're going to be seeing a lot of it when you get home.
Then again, not ALL of their products are packaged in huge bulk sizes. That usually applies to foods. I know some medicines are sold singularly and everyone knows that the furniture, holiday products, and specialty products don't come in bulk.
I love love LOVE going to Costco for their food sampling though! =D I'm such a cheapie. At midday I believe they have an active number of workers set up food sample booths and if your lucky and its the holiday season, you'll find a swarm of people mysteriously gathering and waiting around the cookie sample booth, haha.
Oh, and I bought a really fuzzy cozy blanket last time I went. It feels like a dream =D go buy it!