When a seller offers materials for 0.01 yuan, they’re not making money from that penny—they profit after you click the link.

The penny is bait: you sign up and save the materials, and they earn a referral bonus; then they pull you into WeChat to sell them to you again.

Ask these three questions before buying: Can I see the table of contents? Do I have to add you on WeChat? Is this a referral link?

When you see materials for 0.01 yuan, do you buy them—or ask these three questions first?