So, when it comes to bargains, different people operate in different ways...
Several years ago, when Kodak discontinued Plus-X, I heard about it a bit late. I went to the local stores and bought up every single roll they had. At the time, their stock was expired, so I paid half the regular price for it($3-4 a roll, IIRC). I bought 40 rolls.
Of course, I also passed on all the other inexpensive expired film they had, but I wanted to buy all that I could get my hands on of my favorite B&W film. BTW, I'm not above selling expired film, but I've never sold any Plus-X. I've given away a few rolls to people who wanted to try it, but never sold it.
As discontinuations have rolled in of materials I've liked over the years(most recently was Velvia 100 in 220 last year), I've done the same, but I've also supported some of the re-introductions of the past few years. I bought ~20 rolls of Ektachrome when it was re-introduced-10 by mail order and 10 from the local store. I will periodically buy some from the local store mostly because I want to keep it moving and want to keep them motivated to stock it.
Then there was the time a year or two back when I heard Autozone had the oil I use in the MG on clearance for $1/qt. I drove around to every store in the area buying up all they had. I guess I'm a nasty speculator for doing that, but then anyone who has ever owned an MG knows why I might want to buy oil for it in bulk 🙂