Open price means that an product has not been set to a standard selling price. The cash register asks the employee to enter a price each time the product is sold.
Select main menu Catalog > products
Select "New product" or "New variant product"
Select "Yes" on the parameter "Ask for price", and set Price incl. VAT: 25.
The remaining fields and parameters are filled in as normal
The open price productis now ready to use.