Bulk up
One bulk swap per trip. That's it.
Each purchase, target one item to upsize — something you'll for sure use, that won't expire. The bigger pack pays for itself the second time around.
Every product card already shows the cheapest $/unit pack we've found — that's the swap. Side-by-side pack ladders (84 vs 132 vs 168 vs 252-count diapers, that kind of thing) show up here as we record more pack sizes.