I think part of the problem of the Hogwarts Moments sets sitting on shelves at this point, at least in the US, is the price. I've seen discount after discount on them shared in the UK, but in the US, it's only recently (within the past two weeks or so) that 3 of the 4 of them had any discount at all on them, and that was only at Best Buy and Amazon price-matching Best Buy. And I still haven't seen the Herbology one discounted anywhere, aside from some regional buy one, get one 40 percent off store promotions that haven't been available in my area that the Moments sets were included in. I had been waiting for them to be discounted to get them because I do feel the retail price is a little high, and I snapped up the 3 that were discounted the second I saw them at 20 percent off.
