I snapped this photo while I was in London recently, at the annual LAGB meeting. It's a newsagent just next to Russell Square tube station, and it offers, among other things, 'tobaccos'.
'Tobaccos' is a word you won't hear much. You're far more likely to hear the singular, 'tobacco'. In fact, it's not quite right to call it the singular, because 'tobacco' doesn't usually refer to a single tobacco. It's a mass noun, and what that means is that it's a substance rather than individual things that can be counted (those things are called count nouns!). Water is a mass noun, as is rice, bread, tea, juice, gravel, and so on. Some mass nouns are physically uncountable, like water - it's one continuous thing, unseparable unless you're looking at the molecules. Others, like gravel, are composed of little bits you could count, but we don't refer to each one as 'a gravel' or 'a rice' (for rice, we have a separate word 'grain'). As I've mentioned before, 'pea' is now a count noun, but used to be a mass noun 'pease' before it was reanalysed as a plural, with each individual bit of pease being a pea.
So normally, you can't pluralise a mass noun because it's uncountable. You don't order some rices in a restaurant, for instance. However, there is one time when you can, and that's when it refers to types or instances of a thing. Let's take rice. I wouldn't ask for rices in a restaurant, but I might if I was a rice salesman wanting a wide selection of rices to sell - basmati, long grain, brown, etc. Then I could ask 'What rices do you have?'. Or beer: I might ask for 'two beers, please', and I mean two instances or servings of beer.
This makes me think that this shop might have a wide variety of tobaccos, from all over the tobacco-growing world. Alternatively, it might have been written by someone who didn't know that tobacco is a mass noun and pluralised it to mean 'tobacco products'. This would actually be a perfectly legitimate use of the plural, but we just happen not to use it to mean 'different types of tobacco products'.