The prices of multiple  Supplier items can be edited most easily in a list.

1. Open the Supplier account and click on Purchasing > Product range.
2. Click on  Edit prices in list in the toolbar.
3. Enter an effective date for the new prices at the top of the toolbar, enter the new prices and confirm your changes by ticking the box in the column OK?.
4.  Save your input by clicking on the icon in the top left-hand corner of the input window.