There is only one unit left of HP15c. I found a couple of units in the back of the warehouse, and one has been sold already. Beyond this last unit, nothing else, unless HP reissues it, once again.
The concept of a “Special Edition” or “Anniversary Edition” of a calculator is a concept completely strange for anyone outside our hobby. They see the calculator as a fungible item. They don’t understand how a calculator can cost over 10 €, let alone more than 100.
These same guys may wear a watch one or two orders of magnitude more expensive than that 100 € calculator. I tell them, then, “why do you buy an expensive watch? It won’t go faster than the cheapest quartz-driven digital clock. In fact, it will be less accurate and will require higher maintenance.”
Or they write a Mont Blanc, Parker or Omas fountain pen. Leaky (don’t dare to flight with it in your jacket pocket), requiring frequent cleaning and refill, these have some things in common with our beloved calculators: you can use them for your day job, you can have several of them for different occasions, and you derive your pleasure (also) from their handling: the way a fountain pen slips through the page, or the click of an HP41c keyboard when calculating. But, still, they don’t get it.