I tried searching this topic, but most of the results are on how to get cruise discounts, or excursion discounts.
We had attended a shopping seminar on our last cruise. We were made to believe that it would give us access to "special" discounts. We were given a coupon booklet, but I'm not sure it was worth the 1 hour speech on how great Diamonds International is (and the rest of the partner companies like Effy).
Apart from the raffles that they advertise in advance for port shops, can one get the same deals when it port? The seminar felt more or less like a sales pitch to make purchases, where they will suggest you give them the name of the presenter to unlock some "deals". With all the cruise lines and ships that dock in ports, I somehow doubt that an owner will only offer discounts to a select few if asked.
I agree that someone should purchase items where the price feels comfortable, and I'm also aware that passengers are targets for some stores, especially in the designated port shopping areas.
I know it's a vague question, but any advice on how we can gain an advantage? Off the top of my head, waiting until the last minute might be an example.