Products can be added to different range lists. You can read a further explanation of range lists here.
In your web console, navigate to the main menu item 'Products', and then to the drop down menu item 'Range Lists'.
On this page you'll see all of your current Range Lists.
Double click on your chosen list to edit, or highlight and press the Edit button in title bar. You will see a dialogue box containing the Range List configurable options.
At the bottom of the list is an option for Range List Entries - Press the Edit button.
The next dialogue box shows a list of your products and their prices.
Navigate to the product to which you would like to add or change a price. Double click or highlight and press Edit in the title bar. You will see a further dialogue box where you can change the price list of your product.