There are a lot of marketing gimmicks we have in the US that you don't have in the UK.

Most of my experience was gained in pubs, so let's start there.

In America, you generally expect to get a better price, the more volume you buy. In bars, beer is available in several size glasses (the size varies from one bar to another), but you usually pay less per unit of volume if you buy the larger glass or mug. You can often buy beer by the pitcher--that's around a half-gallon--at around 20% less per unit than buying it by the glass.

In Britain, beer is only available by the pint or half-pint, and a pint costs exactly twice as much as a half-pint. Pitchers aren't available, but what would be the point of buying them anyway if you couldn't save any money?

In American bars, cheap food is often given away free. Popcorn (salty, not sweet) is probably the most common. In the more upscale bars, it might be peanuts or pretzels. The idea is that the salt makes you thirsty, and makes you order more drinks. It might also just be a way of making your bar more attractive than the competition.

I never got anything free in a British pub. You have to pay for every bag of crisps (potato chips) you eat.

American bars, particularly the ones located downtown (in the city center), often have "happy hours" in the early evening (not necessarily only one hour long) when drinks are half price, or two-for-one, and maybe more elaborate snacks are provided free--barbecued chicken wings, for example. The idea is to lure in business at a time when business would otherwise be slow--after the after-work crowd has gone home, but before the evening crowd has appeared. And hopefully, most of those customers will remain in the bar after the end of happy hour and order more drinks at full price.

I never heard of a "happy hour" in Britain, but that comes at a time when British pubs would be closed anyway. Are they still? (I heard some talk about liberalizing the hours.)

It makes economic sense for any business to lower its prices (or increase services) at times of lower demand, and raise them at times of peak demand, just as airlines and railroads do, but British small businesses rarely take advantage of this opportunity. I wonder why?