I buy expensive canned tomatoes, about 33p per can. Other people like to "save" money by getting cheaper, "value" ones at 11p a can. This is false economy! The cheaper cans are made up primarily of weak tomato juice. You're paying for water, essentially. Oh, and salt, of course. The more expensive cans have as much actual tomato as two or more of the cheap ones, so you're actually saving a whole 5 pence per can. Wow. But even that's not a real saving. The tomatoes just aren't as good, so you end up having to add in extra flavourings, even tomato puree, just to make your dish taste of anything. So you come out worse, overall. It's more economical to buy the good stuff and use less.
You do need to make sure that the quality of the can matches the price, though. I recommend Cirio brand. They're certainly available in the UK, and I think the US (and expect Italy) too. Napolina brand are the same price, but not as good.