A wine is on sale when its All Customers price is lower than its Full Price. For example, a Full Price of $45 and an All Customers price of $40 puts the wine on sale at $5 off a bottle.
Put a wine on sale
Go to Settings > Products > Bottles.
Click the wine's name.
Under Pricing, leave Full Price as your normal price.
In Available Prices, find the row with All Customers and a Quantity Required of 1.
Change Price to the sale price, for example 40.
Click Save.
What happens next
Customers pay the sale price.
To end the sale, change the All Customers price back to the Full Price and click Save.
Troubleshooting
Club members are paying less than the sale price. That's expected if the club discount gives a lower price. WithWine always charges the lowest price a customer is entitled to. See How product pricing works.