What it is

A file for an email: a guide, a checklist, a size chart, a recipe book. The Download button appears the moment the shopper signs up.

When to use it

• You sell something people research first (skincare, gear, furniture).
• You can write one genuinely useful page — that is the whole cost.
• Discounts don't fit your brand or your margins.

Why it works

A useful file feels like a gift, not a bribe, and it keeps the discount out of the first conversation. The link is never on the page before the signup, so the list grows for real.