This month, Long's has had various 50th anniversary sales on all sorts of items. It does not look as though you can see their weekly specials online for Hawaii.
I got pretty good deals on Macnuts in clear ziplock bag [$6.99 for 12 oz], Christmas Ornaments, Calendars [.87 or so ea although Wal-Mart also has similar on sale], etc. The specific sale may be over before you get here, but I would check ABC stores, Wal-Mark, K-Mart, Longs, COSTCO and SAMS as your time permits.
There is nothing better than browsing stores in paradise on your vacation. At least you won't get sunburned...
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As an aside to GeorgeBurdell, "Been there, done that [traffic in Atlanta]". On my 1st day of retirement, I was in an 8-car pileup on the Perimeter near Perimeter Mall. I have to admit, that has not happened to me here on the Big Island yet!