Most shoppers understand the general idea that buying in bulk results in lower unit costs. But there is also that point at which any further unit discount isn’t worth the risk or hassle of being stuck with stuff you won’t use.

That’s why many wallet-conscious consumers with occasional bouts of heartburn will buy the large — but not the extra-large — package of acid-reducer pills from their local drugstore.

But as Consumerist reader Anthony noticed at his local Rite-Aid, the store’s peculiar sales prices make that large package of pills a sucker’s purchase.

For customers who don’t use their Rite Aid Wellness+ card, the 30-pack is $7.99 (around $.27/pill) and the 60-pack is $14.99 ($.25/pill). The 160-pack is a huge savings at $.125/pill, but it’s also a huge box and maybe more pills than you’d ever use. Regardless, those numbers make sense.

But for customers using that card that is supposed to save them money, the 30-pack is now $6 ($.20/pill) and the mammoth 160-pack is $12.99 ($.08/pill), but that 60-pack in the middle — the one a customer might just grab out of habit — actually costs $.50 more than the largest size, and you get 100 fewer pills for your money.

So, as always, this is a reminder to read all those cardholder discount tags and sales bursts to see if you’re actually making the best possible purchase.

UPDATE: Consumerist reader — and former Rite Aid shopper — Erik points out that the Wellness+ discount tag for the 60-pack is even worse than what it at first seems:

“It doesn’t say ‘with Wellness+ card.’ It says, ‘save 10% after you earn 250 wellness points.’ That’s right, the $13.49 price ONLY goes to Wellness+ who have spent enough to get those 250 points. Under 250 points? It’s still 14.99, a full TWO DOLLARS more than the big one. THIS IS JUST STEALING FROM OLD PEOPLE WITH BAD VISION.”

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