I collected Hawaiian shirts from goodwill-Sally Ann shops in Hawai'i, but about 1990, as they became sought after on the mainland and a book about them came out, those with interesting and rare patterns disappeared from second-hand stores and started showing up on Ebay and in boutiques at much elevated prices.
The most sought after and expensive are some of the old rayons but for wearing I prefer the well-made cotton Reyn-Spooner shirts, which I still wear during the brief summer here in Canada. Some silks were also sewn in Hawai'i.