Hi
it really depends on when you go, if you go during Food & Wine Festival
the cost will depend on the size of the drink your ordering.
my experience,
i drink the 3oz beers which i believe are around $3 and i find i can drink a 3$ beer per country at the world showcase as during Food & Wine the kiosks are closer together in between the countrys.
the food items again can vary, depends aswell if you have dining plan? we used our snack credits at world showcase during Food & Wine last year and this helped keep the cost down too.
all in all we spend for 2 of us on a 2 week vacation around $300 at epcot, which i think is pretty reasonable.
i go during Food & Wine Festival and have a blast every year.
we are planning on upping our allowance for Epcot this year to $400 dollars so we can each have a gift card with $200 each as this has now become one of our main reasons for coming to Disney in the fall.
hope the above helps