Yes, Costco is great in the UK too. There are fewer stores, so I didn't go as frequently as I do now I live in the States, but prices are very good and discounts comparable with here. The main difference is that they have less organics and specialty items in the UK stores. I suspect this is because the customers tend to be business owners rather than general consumers - British homes have little storage space and are generally much smaller, so the average person just can't bulk buy. Definitely advise shopping there if you want a good deal, though. Also check out Aldi and Lidl.
