See how you can calculate the sale price based on the cost price using markup.
Markup is a percentage (%) used to automatically calculate the sale price by adding a profit margin over the cost price. A 10% markup means the sale price will equal 110% of the cost price. For example, if a product costs $100, a 10% markup results in a $110 sale price.
1. In the product registration form, fill in the Cost field.

See here how to register a product.
2. Check the Automatic option next to the Sales price field.

3. In the Markup % field, enter the markup percentage for the product.

Markup is entered as a percentage, which will be added to the Cost price to automatically calculate the Sale Price. See here how to set a Default Markup.
4. Click on Save - F2.

Done! Your product's sale price has been generated based on the cost price and specified markup.