I was under the impression it was quite a good snack, as 100g is loads of popcorn! According to my carbs and cals book, a bowlfull of buttered popcorn weighs only 30g and is 15g carbs. So if you had a maker at home you could just do a small amount and it wouldn't be many carbs.
Not sure about healthy seasonings, how about cinnamon or something herby?