If you at a later point want to show the price of a particular product, enter it at the usual place for that product and then go to CATALOG > CUSTOMER GROUP CATALOG > RULES on the main admin menu.
Click on the ‘hide prices’ rule that is there:
Then click on the ‘product access restrictions’ tab. Find the product you want to show/hide the price for and check/uncheck for that particular product. Checked off means that the price/add to cart button is hidden. Once done, hit the ‘save’ button.