For the deluxe meal plan you'll be getting 2 Entrées (can be $12-15 each), a snack (pretzels are amazing here! Can be $3-5), side/dessert (also $3-5), and the souvenir drink cup ($12, and free refills all day). All for $33.59 (adult) and $25 (child), so you really are saving the money, and worth the purchase! I had friends from TX just use it last week and they loved it!
My favorite places to eat would have to be Trappers in Aquitaine/New France and Marco Polo's Marketplace in San Marco/Italy.
You can buy it at the park, but I would suggest buying it online, sometimes it can save you a quick buck and any lines or extra waiting at the park.
https://seaworldparks.com/en/buschgardens-williamsburg/book-online/extras/diningplans
Good luck and have fun!