I think that depends on where you are and what you decide to eat. When I worked downtown, I'd go to Marukame Udon and get a large bowl of noodles with meat, egg, some calamari, and a drink for about $9. I never finish my noodles and end up having enough for the next day. I went to Times a few days ago and got a plate of ribs, two scoops of rice, veggies, and a drink for $7. I think that's quite low even for mainland standards.
I find this an awesome comment. We used to live in Kailua, and ate out a LOT (some weekends, we'd splurge and go to Waikiki for drinks and pupus, and spend like $50 but that was 20 years ago).
We eat at local spots when we're out, and the prices are no more than here in Maryland at all. Sushi Bay in Kapolei is great for good tasting, very inexpensive sushi (we used to love Genki Sushi, but their quality is no where near as good). There are lots of good Korean places too (husband is Korean, and we love barbecue). Some take outs, like Yummy BBQ type places, have great plates for very reasonable prices.
If we eat out, it's usually lunch if we're out in town, but for dinners, we cook or grill or do leftovers, or some stuff from Costco. Our trips to Hawaii actually cost us less than our trips to Disney (disclaimer: we go to the Marriott Ko Olina where we own, but still it's right there in Kapolei).
And, I despise the food at the Marriott. It is overpriced, and pretty bad. Never eaten at Aulani, looked into it, but I don't do well at buffets much as I'd eat a little and be done so not worth it. Not worth $200 for us to do a buffet.