Seems pretty close, at least from what I've seen in my area.
I carry a $1M per occurrence, up to $2M per year policy that covers liability at my restaurant, plus outside vending, and that runs me close to $1,900/year. But I also have additional endorsements for damage I cause to spaces rented out to me at an event, extended coverage for employees driving non-company cars, etc.
So if you're looking for liability insurance that strictly covers vending, those prices don't seem too out of line. Some of the really low quotes you may find people talking about might be basic umbrella policies, not necessarily commercial liability policies.