If you have a house or condo, go to Rippon's seafood and get carryout. We always go there once or twice during our beach week and have a seafood feast on our balcony overlooking the beach - much better quality seafood than you'll get at the tourist restaurants, and better price. You can check their menu online, but they'll have hard crabs, steamed shrimp, crabcakes, crab deviled eggs (yum!), fresh fish and crabmeat (if you want to cook). Their backfin is awesome, full of huge lumps. I always bring some home with me.
ETA, just thought of a couple of other things:
Anthony's Beer Wine and Deli on 32nd has good carry out sandwiches.
Minit Market on 31st, makes their own doughnuts, soooo good, get there early, 'cause they run out. I much prefer them to Fractured Prune as they're not overly sweet.
Also, we usually order a humongous pizza from Captain's Pizza (32", I think?). The kids always ask for this, they get a kick out of it because the delivery guy has to turn it sideways to get it through the door. It feeds a ton of people and is good pizza to boot. Their cheese steaks are good too.
We always spend a night on the boardwalk eating junk for dinner - Thrasher's fries, Dumser's ice cream, some caramel corn or taffy from Dolle's for dessert - and come home with a bellyache!
We are there every year, but most of the time we eat at the house - don't want to waste our beach time in restaurants! I just remembered I typed a big post last year about inexpensive things to do in OC. I'll link to it, but Dis has search disabled right now. They have a great website with lots of inexpensive things, my kids have enjoyed many of these:
http://ococean.com/things-to-do/100-free-oc-activities
Are you doing Starpower? My oldest DD is a dancer, and we used to do that one every summer. She's all grown up now!