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Refills are not cheaper on day one

And that is the whole design. A refill system front-loads its cost: the first purchase buys something durable, and everything after it is just the product. So the first receipt looks bad and every receipt afterwards looks good. The question is how many refills until the two even out.

Free, no account, and nothing is saved or sent anywhere — the maths happens in your browser.

What you would pay for the normal version, each time.

The first purchase: the bottle or dispenser, plus its first fill.

On its own, without the bottle. If that is hard to find, that is information too.

Level after 6 refills.

The starter kit is $12.00 more than a bottle — so you start $12.00 down, and each refill saves $2.00 against buying another bottle.

Inside a year at the rate you gave — the kind of commitment that usually sticks.

Optional — turns refills into a date.

At that rate the crossover is about 11 months away.

These are example numbers — change any of them.

Worth knowing either way: the good brands publish refill prices plainly, because the maths flatters them. The Green Diaries has the argument this came from.

Comparing two packs on a shelf instead? Price per use is the one for that.