If I understood your question right, that you only want to see the sold iPhones when you click on iPhone in the Products List, then I would recommend you to use WebPart Connections.
This blog post shows (with screenshots) in Part 5 how to connect the WebParts.
Use Connected WebPart Feature in EditForm.aspx
Prepare List for changing EditForm.aspx
Go into the List settings --> Advanced Settings and on the bottom you should have a point called something like Show Forms in a dialog and set it to No.
Go into Edit Mode of the EditForm.aspx
Go into your products list and mark a list item and click on edit. When the EditForm.aspx opens for changing the list item go to Site Actions --> Edit Page. You are now in Edit Mode of EditForm.aspx and as you can see there is already the "Products"-List WebPart on it.
Add the "Products sold"-List WebPart to the EditForm.aspx
Just click on add a WebPart and choose the "Products sold" List.
Connect the WebParts
Connect the WebParts as described in Part 5 in the link above. In your case the the provider field name and your consumer field name has to be set to "Product name".
Leave the Edit Mode and change the List settings back to "default"
After adding the "Products sold" List WebPart and connecting the WebParts click the "Stop Editing"-Button in the Ribbon. Go again to the List Settings --> Advanced Settings and change the Show Forms in Dialog to Yes back again.