cheap places for good food on the north shore oahu
The three best known places for cheap food (cheap by hawaii standards) in Haleiwa - the center of the North Shore - are Kua Aina Burgers (the have various kinds of sandwiches as well), Opal Thai (a lunchwagon/food truck), and Macky's Shrimp (another food truck.) Some of the other shrimp trucks have opened in Haleiwa, but Macky's is the oldest and arguably the most popular. Grass skirt Grill gets fair or better reviews for the most part, but I've never been. Cholo's is often touted, but got a scathing review by a former chowhound poster. Pizza Bob's used to be good, but in recent years the reviews have not been good. Maybe a change in ownership? Killer tacos also used to get better reviews. There is also an L&L drive in, not a favorite of mine, but lots of people like it.
There is supposed to be a North Shore farmer's market that started recently in Waialua, I don't know any of the details, but it would probably be worth looking into.
If you head down toward Sunset beach/Waimea Ted's pies is worth visitiing, if only for the pie. I've never had anything else from there, but have heard good things. The Foodland Supermarket in Sunset Beach has a good seafood dept.
Further down, around Kahuku are more shrimp trucks, including Giovanni's. And in the Sugar Mill there is a curry restaurant that is supposed to be really good.
It's been 7 years since I moved back from Oahu, so my restaurant recommendations probably wouldn't mean anything.
To answer your other question, yes, I think you should easily be able to get fish and cook it yourselves. Fresh fish is for sale everywhere (maybe you can find a specialty place on the NS, otherwise the supermarket should have good stuff), and there is a big local cookout culture, which means outdoor space for grilling is abundant. At worst, you might have to invest in a cheap hibachi (also for sale all over the place). Another option is to just go raw, as in sashimi or poke, also available in most grocery stores. I'm jealous.
Hope this helps!
at Romy's (and maybe Fumi's) you can buy fresh (live) shrimp and prawns raised in the ponds right behind those shrimp stands. Not very expensive, either.
Cannot say if these folks are out there on weekdays, but usually on weekends a few people set up tents on the north side of Hau'u'ula - right at the end of 'Aukai beach park on the mauka side of the road. Coolers full of fresh fish...depends what the catch is....last time i went past i stopped and picked up what was easily 2 pounds or so of fresh mahi for 15 or 16 bucks. cant beat that. That day they also had plenty of Aku (skipjack tuna)...which some say is a required, gamier taste than ahi, but i tried the aku poke they had there and it was FANTASTICally good. the aku has a bit more of its own flavor going on compared to the more neutral ahi. made excellent poke.
Tamura's just a bit farther north than that usually has whole local fish for sale, including a lot of reef fish that are most def an acquired taste. but it would be worth picking up an Uhu (parrotfish) if they've got...somewhat mild, white flesh. plus, best beer prices and selection up there.
an interesting spot to check out is the FIJI Curry market in the kuhuku sugar mill. lamb curries,roti, meat pies. and a whole market full of fun spices etc...can pick up some spices or other ingredients for your fish....