I've been building these RTC breakout boards, which require a small Schottky diode. Nothing special, pretty generic requirement.
Shopping at Mouser, I find a suitable one that costs $0.04 or $0.05, and I order a dollar's worth. Most of a year goes by, and I run out of diodes. I go back to reorder, the same part is now $0.37 each and still over $0.20 in quantities of 100.
I don't think much about it, it's easy enough to find a suitable replacement, and I order a dollar's worth of another diode for $0.04 each.
Months go by again and now the second diode is $0.26 each and nearly $0.15 in quantities of 100. Lather, rinse, repeat, I find a third diode but I'm getting miffed now so I order 100 at $0.04 each. At least I won't have to go through the rigamarole quite so soon next time.
I wonder whether anyone can explain what's going on. It's also happened with other generic parts, e.g. 100nF MLCC caps, thick-film resistors, etc. A variation on the theme is when I go back to reorder, the price is about the same, but now there is a minimum order quantity of 3000.