OK, you're going to need to display the data in several columns before you make a Pivot table out of it.
One Column for SalesReps with the Column Name SalesReps, One for Shoes, One for Socks etc etc ...
You can only have one name for your Products fields, but you can rename your Columns to something like 'Products / Shoes', Products / Socks if that's useful to you.
I'm using Office 2007 but it is similar in other versions.
Select the Cell that contains the name 'Shoes' for example, right click & select Field Settings & you can rename that field.
Hope this helps you, Cheers