Tryvertising adds sample ordering to a WooCommerce store. On a product that has samples enabled, customers see an “Order a sample” button. They can order a free sample, a paid sample, or a mix set by the shop: a set number of free samples first, then paid samples after that.

What the free version does:

Set a sample price per product or per variation, free or paid.
Offer a set number of free samples first, then charge for further samples (tiered free-then-paid).
Limit how many samples a customer can order per order and per customer.
Keep sample orders sample-only: a cart that contains samples cannot also contain full-priced products, and a cart with full-priced products cannot add samples.
Sell swatch packs: a pack product made up of sample components.
Issue an automatic, single-use sample-credit coupon when a paid sample order is completed. The coupon is for the sample amount only, is restricted to the sampled products, and expires after 30 days.
Show a sample-to-full conversion report under WooCommerce > Sample Conversion, so you can see which sampled products led to full orders.

The credit is calculated net of tax. If part of a sample order is refunded, the credit is reduced to match what was kept; if the sample is fully refunded, the coupon expires.

Please note the limits that apply to this version:

Classic forms only. This plugin works with the classic cart and checkout. It declares the cart and checkout blocks incompatible, and the sample button does not render on a block theme.
Guests cannot redeem an email-restricted sample-credit coupon. A coupon issued for a sample order is tied to the email address used for that order. A guest customer must log in with the sample email address before the coupon can be used at checkout.
This plugin requires WooCommerce 8.8 or later, and has been tested with WooCommerce up to 11.2.1.