Advertise that for today (or this week) this product can be bought by what the customer thinks is the fair price. The product should not have an MSRP printed on it (like a book), and an important part is, that they read (and maybe sign) explanation for why you are doing it. Most important, is including what is involved in pricing a single product in the shop (explaining the cogs, how long they stay on the shelf on average and how much that costs, shipping to the store, cost of money “sitting in it”. Basically, show them the real cost for the store of offering them the product.) Then they can buy it for what they think is fair.
An analysis should follow this experiment to find out if there are interesting patterns of behavior.
Offer them the following: they can get the product they chose for the regular price, or they can buy another product (either the same or another) and get a nice discount for both, but only if the second one is going to be a gift for someone. If it’s a consumable, you might want to have a permanent sticker on it saying “A gift to X from Y – brought to you by YOUR BRAND NAME” so they are more likely to gift it. If it’s not and it’s the same product (like two copies of the same book), then that is optional.
In any case, even if they don’t gift it, it will still help grow your transaction size. If they do, it will also help you spread the word about you and the product.
Encourage people to buy on the first day of availability (or pre-order), and make these into a collector’s item.
Print special dust covers that only those who buy the book on the first day get.
Can also be done with other products like games, playing cards, toys, etc.
So people can find new interesting ones and also publish their inventions.
A website that lists and shows classical mechanical puzzles, and allows anyone to publish their inventions. You can also get help solving these puzzles.
Most trend analysis is being published by someone who has some other agenda, and that skews the results.
Start with particular interest area(s) like fashion, online games, technology, etc. The main important point is that it is independent. It’s vetted and curated by experts in the field who are also vetted for no hidden agendas. This will give you a clear view of fads and trends.