You can change the ‘Regular’ (or ‘Suggested’) selling price of any item by pressing <Home> while that item is highlighted. If you have used a valid SKU number, the price should already be correct so you shouldn’t have a need to change it here. If you used a dummy SKU number, you may very well want to change the regular retail price since the dummy SKU number will have a zero-price.
Changing the regular selling price of a sales item does not change it in the inventory file. The price entered here is used on the customer receipts and monthly statement to indicate the usual selling price if you give the customer a price lower than the regular selling price.