If you paid for something at the and advertised price then only received 2/3 of it would that not be crooked?

Someone not far from here won that big lotto last week. It was advertised at 360+ million. Why did they only get (after allowing for 2 winners) then only about 2/3 of the promised amount. I am typically not a gambler. My curiousity is based on what the meaning of "Scam" is? If a Jiffy store advertised milk at $4.29 a gallon and you went to buy then they said "here is 2/3 of a gallon, that would seem like fraud to me. If I went to buy a dozen eggs and they advertised at $1.98 a dozen and I only got 8 and 1/2 eggs... I would not shop there any more. Does the states not have to comply with truth in advertising?