How do I let gift card buyers choose their own amount?

This needs the Gift Cards plugin. Open the product and find the Gift Card card on the right.

1. Tick This product is a gift card.
2. Enter Min amount and Max amount, for example 500 and 5000.
3. Click Save.

The buyer enters the recipient and an amount within that range. A real gift card is issued when the order is paid.

If you leave Min amount and Max amount blank, the gift card is sold for a fixed amount equal to the product's Price.