Ok, I've seen these discussions before, and never paid much attention, but I picked up a Costco membership for $60 with a Groupon. I know Costco has it's adherents...so what's the best deals things going at Costco, primarily in terms of saving? It's not too far away, but we won't be going there for our regular weekly shopping...what's really worth stocking up on say once a month? Or what's much better at Costco than a grocery store?