You can sort the items in your filters by any of the properties you uploaded, price, item code, and more, in descending or ascending order.

Go to Items -> Manage Catalog.

Click on the Filter you wish to sort the items in and click on the Edit Filter icon:

Go to the "Sort By" section of the filter:

Select a property to Sort your items by.

You can also indicate ascending or descending order, by selecting the up or down arrow.