Count the first fill once. Compare both running totals at the point when you expect to stop buying.
Read the small number on each package
Set the regular bottle, filled starter and refill side by side. Write down the net volume and the price you would actually pay for each. A pouch is a package, not a unit: one pouch might fill your bottle twice. The Canadian Office of Consumer Affairs explains unit pricing using groceries; the same arithmetic works for shampoo. Divide the price by millilitres, then multiply by 100 for dollars per 100 mL.
Follow the money through four fills
Suppose all three packages hold 250 mL. A regular bottle costs CA$10, a starter with shampoo costs CA$16, and a refill costs CA$7. These are invented numbers for the calculation, not Canadian retail quotes. Assume no extra fees and that you use every fill.
At 250 mL, the starter route costs $16 versus $10. At 500 mL, it costs $23 versus $20. At 750 mL, both routes cost $30. Only at 1,000 mL does the refill route pull ahead: $37 versus $40. The second refill recovers the premium; the third produces the first saving.
A worksheet for your shopping list
Copy these four lines into a note: regular price for one fill ___; starter price including the first fill ___; refill price for that same volume ___; number of refills I expect to finish ___. Multiply the last two numbers and add the starter price. Compare that with the regular price multiplied by the total number of fills, including the first. If the dispenser is sold empty, add its first fill before you start.
What if the pouch is bigger?
A 500 mL pouch at $14 works out to $7 per 250 mL. But you pay $14 at checkout. If you only use half before changing formulas, the other half has not saved you money. For a cash budget, compare whole packages at checkout and note how much would remain in each. Include delivery and any required accessories on the side that incurs them.
Decide where to stop counting
If you expect to switch shampoos after the starter and one refill, the regular bottles win in our example. If you already own the compatible dispenser, today’s choice starts with your next purchase; you need not buy the starter again. Neither result tells you which formula will suit your hair or which package has the smaller environmental footprint.
AI-assisted editorial guide. No affiliate links, sponsorship or hands-on testing.
Sources & editorial notes
- Office of Consumer Affairs — Comparing food prices: Per unit pricing ↗
Unit-price method; the shampoo example and worksheet are original.
Prepared with AI assistance and checked against the listed sources. This is not a hands-on product review or a dermatologist-reviewed article. Last substantive review: November 10, 2026.
