Make a custom sale in Shopify POS
You can use a custom sale item to enter any price for a transaction.
On the Shopify POS screen, tap Add custom sale.
Enter an optional title for the sale and the sale price. You can also adjust quantities or if the item is taxed, if necessary.
Tap Add to cart to continue with the transaction, or tap Cancel if you want to discard the custom sale item and return to the main Shopify POS products screen.