Where these products are actually cheapest
No wall of promo codes. Codes expire, they exclude the item you came for, and the pages that host them are built to catch a search query rather than to answer one. What is here instead is the structural version — which type of seller wins for which category, and what to check before you commit — because a channel that is cheaper every month beats a promotion that is cheaper once.
The four channels that matter
The gap between these channels is wider than the gap between most brand promotions, and it recurs every month rather than once a year. That is the whole argument for caring which seller you use instead of which coupon you found.
Medical supply retailers
Sellers who stock incontinence products by the case instead of the pack. For anything a household reorders indefinitely, this is the single largest price lever available and it is worth the ten minutes of comparing case sizes against unit counts, which is tedious in a way that a two-dollar difference per box is not.
Case sizes vary and some manufacturers use different product codes for institutional packaging. Confirm the unit count, and confirm the case is the same product as the retail pack rather than an institutional version of it.
Brand-direct subscription
Buying direct usually beats retail on price per ounce. Subscription is how brands make that comparison harder to run.
Three questions before you commit: what is the minimum number of shipments, what does it cost after the introductory period, and does the refill cadence match how fast you use the product? A thirty-day cadence on a six-week supply builds a stockpile you paid for and did not need.
Optical retailers with in-house labs
For reading glasses the channel barely matters. For prescription eyewear the lab and the return policy matter more than the sticker price does, because the thing you are buying is a measurement and a remake if the measurement is wrong.
Pupillary distance. A seller who does not ask for it, or who offers one bridge width for all faces, is a poor fit for anyone who is not average.
Warehouse clubs
Cheapest per unit on a handful of high-volume items.
Three products wide, and the selection rotates. A club that stocks your brief this month may not in March, which is a bad property for something you reorder forever.
By category
Each section carries the full buying decision, not just the price.
Eye Care
Five dollars or a hundred and fifty. The optics barely change.
3 guides →Home Care
Bought monthly for years, usually on bad advice.
3 guides →Sleep
Sometimes a nuisance. Sometimes a symptom. The difference matters more than the product.
3 guides →Skin & Personal Care
Sold on stories. Priced by the ounce. Judge it by the ingredient list.
3 guides →How to tell a real discount from a pricing illusion
Most "deals" in these categories are not discounts on a price. They are discounts on a price that was set higher in order to be discounted, which is a different thing wearing the same word.
Three checks catch nearly all of them.
Cost per unit, never pack price. A pack that is 20% larger at 10% off costs more per unit than the one beside it. This is the most common mistake in the category and it is not a stupid one — the pack sizes are deliberately not comparable, and the shelf is arranged so you reach for the big number.
The item's price history, not the banner. If something is on sale every week of the year, the sale price is the price and the crossed-out number is decoration.
Value the free gift at what you would pay for it. A gift worth $40 that you would never have bought is worth zero to you, and it is usually priced into what you are buying.
9 brands get referenced across the guides here and some of those references are affiliate links. Buy through one and we may earn a commission at no extra cost to you.
Where a cheaper option exists outside our partner list, the guide says so. Where something is not worth buying at any price, the guide says that too — which is the part that makes the rest of it worth reading.