Struck-through prices, and when we show one
A crossed-out price is the cheapest persuasion there is, because it costs nothing to invent. Here is our rule for showing one.

A price with a line through it tells you two things: what you pay, and what you are being told you saved. The second number is the one nobody checks.
Why it is usually fiction
On a digital product there is no manufacturing cost and no stock, so the regular price is whatever the vendor types. A launch price that never rises and a regular price that was never charged are both extremely common.
What we do
We only show a struck-through price when the vendor publishes one themselves, and the listing says so in the price note. If it is the vendor's stated value rather than a price anyone was charged, we write that too.
What to look for elsewhere
If a sales page shows a countdown timer that resets when you reload, the deadline is decoration. If the was price appears only in the graphic and never in the checkout, it was never charged. Neither means the product is bad — it means the discount is not evidence of anything.

