Dining locations, other than the main dining room and Windjammer (bolded = no extra costs to all guests):
Giovanni's Table - Tuscan Italian restaurant, which is open for lunch and dinner. Costs extra money
Park Cafe - opened for breakfast and lunch. Sandwhiches, soup, salad, fruit, pastries. Will also offer snacks until late at night on some nights. This place is complementary.
Chops Grille - Steak house that is open for dinner. Costs extra.
Sabor - Mexican food that is open for lunch and dinner. Costs extra.
Izumi Hibachi & Sushi - Japanese food open for lunch and dinner. Costs extra.
Sorrento's Pizzeria - open 24hrs, with pizza by the slice or you can even order your own custom made personal pizza. No extra cost.
Café Promenade - open pretty much all the time except for really late at night. Free snacks, pastries, and sandwhiches. Specialty coffees for an extra cost.
Boardwalk Doghouse - Hotdog stand that offers various types of franks and sausages. No extra cost.
Cups & Scoops - ice cream and cupcakes for an extra cost.(There are free soft serve machines on the pool decks)
Johnny Rockets (only free in the morning) - in the morning, this is a free place to get breakfast. There is an extra cost for lunch and dinner.
150 Central Park - Extra cost, multi course meal. Supposed to be really good!
Solarium Cafe - open for lunch at no extra cost. Sandwiches and such. It is right outside the adults only area.
Wipe Out Cafe - open for lunch and later. Burgers, hotdogs, and more. This is over by the Flowriders. So it is a good place to grab a bite and watch others.
Coastal Kitchen - only open to suite guests and those with Pinnacle level
As others have mentioned, your daily compass will show hours and will mark which ones cost extra.