I think the word you are looking for is "offerta," at least that's what I saw in supermarkets when food was marked down. There is another term I saw on menus, similar to "plat du jour" from French but I'm sorry, I don't remember it.
With regards to occupation, I think this is a particular type of skill. E.g. an engineer who specialises in materials science, or a doctor who specialises in cardiology.