Why the pack price says little
The price on a listing refers to a pack, not to a period. Two products with the same pack price can differ fourfold in how long they last if their directions differ.
The meaningful figure is the price per daily serving: the final price divided by the number of days one pack covers when used as directed.
The calculation for this format
A pack contains 30 capsules. The directions state two capsules daily. That gives 15 daily servings per pack, so one month requires two packs.
Divide the final price including shipping by 15 to get the daily price. Compare that figure with other products rather than the number on the front of the pack.
Shipping, payment and hidden commitments
The real cost includes shipping, any surcharge for a payment method and the cost of returning goods if the seller does not cover it. A low headline price with high shipping is often more expensive overall.
Watch for subscriptions. Some sellers pre-select a recurring delivery in the basket. Before paying, check that a one-off delivery is selected and how cancellation works.
Reading price claims correctly
European price indication rules require that a price reduction states the lowest price of the previous thirty days. A permanently struck-through reference price that never applied is not permitted.
Prices change. Any price on an information page is a snapshot and must be checked again at the seller before ordering.