I'm sure someone was complying maliciously here, but I'm not sure who.
Everything in the store was on 'sale'. What they do is mark up the price, then discount it back to the normal price. For every single item in the store. So there are hundreds of these little printed standee signs everywhere next to each little thing.
Looks like management forgot to define a markup+discount to an item, and a programmer and/or sales staff just abided by the ridiculous 'everything must be on (fake) sale' directive.
If that's a genuine Tefal 24cm pan, that's still an amazing price.
Roughly 🇺🇸$20.65.
It probably is at that retailer -- although that's not that good of a price for a good pan locally.
The Vietnamese market is super demanding when it comes to these things, it really drives price down and quality up. I bought a large, quite good, enameled cast iron pot recently for less than this pan costs :D