IF (and it is a big if) you have access to a freezer, you can also buy in bulk items with large season fluctuations in price (strawberries, apples etc.)
Technically, I guess I have a half-sized "chest" freezer in my basement, inherited but never cleaned or used by me. I just use the freezer that's part of my fridge.
One fruit that freezes great, and is actually difficult to find at the wrong time of year, is cranberries. Just after Thanksgiving or Xmas, they're usually like two bags for a couple of bucks, so I'll buy them up and freeze them in one cup bags -- exactly the amount I'll need to bake a lemon-cranberry loaf in the spring.
The underlying problem with the advice to "purchase in bulk" (whether it is something that can be frozen or not) is that those who can most profit from it usually do NOT have the surplus money on hand to actually do so.
I get that, and I certainly wouldn't suggest to such folk that they need to buy a side of beef to save money. And at a certain point, if you don't really have enough money to eat, you surely won't have enough to buy meals for next week. But when ground beef is $2 a pound, if you can buy an extra pound and freeze it then it's going to save you $2 next time you need ground beef, which you can then use to stock up on something else and so on.
I went to the Bulk Barn chain and was able to purchase the spice loose for $2.38 per 100g - a 700% difference.
Good discount. Another great thing about "bulk" places -- you buy what you need.
That said, I just recently discovered that one of my favourite Portuguese groceries sells pretty much all of its spices for $2.19. You might get more dried oregano than saffron, but all the packs are the same price. I like that.
Best place IN THE WORLD for a lot of spices? An Indian corner store. Good chance they'll be in plastic cups with plastic "take out" lids or whatever, but cardamom and cinnamon and a whole whack of others for so very much less than anywhere else.
and I suspect that it not because the house brands in supermarkets are bottled in hand-blown Bohemian crystal containers...
My herbs and spices are all in fancy containers from the House of Mason. Infrequently used stuff in salmon jars, common stuff in jam jars, the very popular stuff in pints. Most of them I didn't pay for at all -- people seem to throw away mason jars all the time. Maybe they're like coathangers or shopping bags to some people.