as moni said, it does depend the the type of traveler you are.
sitting down can range as widely here in Antigua as at home.
diner style = local fare
roadside when carefully referred, is an excellent way to inexpensive eats.
Samir's on All-Saints road does a great shawarma and pretty good (reasonably priced) pizza
this morning i had a terrific sandwich at the ladies down in front of the post office $8 EC = approx $3.50 US. excellent.
that's a bite to grab.
sit down at Delightful chinese food, cost us $90. EC = $33. US, for 3 plates + appetizer + 2 soft drinks. it was okay.
OJ's is very reasonable for beachside, sit-down. be patient.
THE GALLERY is a bit more, and very good.
LIFE BAR does very decent Indian food.
none of these exceed what you'd pay at home.
groceries can be a bit more. but if you want the same (processed) foods that you get at home, be prepared to pay more. they have to ship it down.
FARMER'S MARKET saturdays has all fresh produce. check it out (any day, but the choice varies from day to day).
EPICUREAN is great for selection, but not the cheapest (cheaper up north than jolly harbour).
BAILEYS is your best bet for market in the south.
GLORIA'S is more local, much cheaper, lacks the selection of visitor may want.
all the best.