When a product’s price seems too good to be true, they’re not selling—you’re the ad

When you see a promotional product priced shockingly low, it means they’re not really selling anything—they’re running ads. Spending ¥50 becomes:

Spend ¥1, leave a review, save it, add to cart, share with a friend, join a group buy, complete mini-games, and so on.

In plain terms: when you spend little or nothing, you become the ad space—and ad spaces do what ad spaces are supposed to do.