We are into our 2nd week here right now! It is wonderful!
I echo what everyone says. Grocery stores,
Walmart etc are not any more expensive than at home. We also pick up all the coupon books available. You will be surprised what you find.
Atlanta Bread (like Panera) has a 20% off coupon if you go after 5. beware they close at 8.
Tons of early Bird specials if you can roll off the beach and get to the restaurants by 5:30 or 6. We ate at the Japanese place for $12.95 each and it was yummy.
The Tanger outlet book has 10% off at the Westin restaurant, Turtles. Today we are going to the beach and will pop in there for lunch then do sandwiches for dinner. We are in Port Royal, so it is perfect for us.
The Wendy's has all you can eat Chili and a small drink for $1.99 on Sunday and Monday after 4 or 5. We did a baked Potato bar and grabbed a couple of Chili's (you can get 2 small Chili's for $1.99 for this deal at the drive thru) for toppings.
Our fav Mexican place is Mi Tierra, it looks like a hole in the wall but is pretty good. (It is down near the crazy crab -- not the one in Harbour Town)
Street Meet near Sam's Club is yummy. The pretzel and Crab dip are Awesome as is the grouper sandwich. 2 could share this. The Crazy Crab is also great.
We come every year, so eating out is not a priority for us. We eat mostly in the condo and do not bring from home. I usually need to visit Walmart as we will run out of something...most likely sunscreen. I started with 18 bottles for 8 of us and am down to 4 after buying 2 at Walmart last night! LOL!! Although I think there are a few stray bottles in beach bags and bathrooms!
The best evenings (and they are free) is a night under the big tree in Harbour Town with Greg Russell nightly 8 pm. Get there by 7:30 for a bench seat. Shannon Tanner in Shelter Cove nightly at 6:30 and 8. Fireworks on Tuesday but it will be REALLY crowded.
OH...My ice cream tip. My DD wrote at school about her summer and how we had Ice Cream EVERY night on vaca!!! Well, that is because DH took them to McDonald's for $1 cones or $1.79 Snack size McFlurry's!!!

My kids don't need those $8 cones to feel spoiled!!!
Finally for you Disney Fanatics. IF you go to the Disney Resort...a short walk from Shannon Tanner and Shelter Cove. You can enjoy a Mickey Bar or and Itsakadoozie. just pop in and it is above the pool. Ask, they will point you in the right direction. Or you can go to the Disney Beach (no different except they have a snack Bar with Disney Ice Cream (and Disney Prices!) Beware though, your Kid's will beg to stay at Disney because the Pool has a DJ and it is rockin and sounds like TONS of Fun While you sit outside eating your Mickey Bars!
Enjoy your trip!!!