Open the stock item, scroll to pricing section and open it if it is collapsed. Click the ‘+’ icon next to add pricing and, select retail, add the price and choose your tax rate.

You can add more pricing tiers if you also sell your products at a wholesale or distributor rate, and if you want to track your cost of purchase for profitability reports.
If you need to add more pricing tiers please create a support ticket and our team will add them for you.