Apparently these are the must-have gadget for 2017, though I only heard about them last week, fashion-unconscious as I are. There are a few types, but the most common seem to be the trilobal types, three blades with a bearing in the middle. I did a bit of searching and there are cheap ones, super-expensive ones, YouTube channels that review them and discuss the merits of ceramic vs standard bearings, and contests to see who can spin them the longest.
https://twitter.com/fingerlabzcom/status/856585180277899264
So I was in Dundrum Centre today, remembered that there is a gadget shop there, and thought I might try one and see what they cost. Nope: signs stuck to the counter saying "sold out till Thursday". Oh well. I wonder what it would cost me to ship a box of them from Alibaba in China, so I could resell them on eBay?
Nah. By the time they get here, the trend will be over, and it will be on to the next thing. Yo-yos are due for a comeback. The whole Fidget Spinner thing has blown up so fast that even with-it teenagers are going "wot?"