If you are only planning on going for one day and aren't a local that should have a AP anyway, don't even bother. They streamlined the pricing years ago so that it's really only reasonable to go for 5+ days.
Our family got park hoppers this past February when they went with us and were shocked to see that it was literally only $2 more (yes, as in $2.00) to go from a 5 day to a 6 day park hopper. Once you hit that many days, its still a bargain IMO but hasn't been a 1 day visit without an AP for years.