O'ahu Grocery Shopping on a Budget

Hi everyone, I wanted to ask where people on O'ahu are doing their grocery shopping to maximize their budget. I used to shop wherever was convenient to save time, but now I'd rather save cash. Aside from Costco and Sam's for bulk items, when and where are you folks going to buy specific items? So far I've seen that Target has good prices on pantry items under their store brand, and Safeway sometimes has good Buy One Take One coupons and their bakery items go on sale on Fridays. Any other money-saving tips would be appreciated!

EDIT: Wanted to mention that I shop only for myself as I live alone!