Costco offers its members the Fila Women's Slip-On Shoes in Black or Grey for $15.99 with free shipping. (Non-members must pay a $4 surcharge.) That's the $4 off and the lowest total price we could find. They're available in sizes 6 to 11. Deal ends March 24.
Fila via eBay offers the Fila Women's Headway 6 Trail Shoes in Navy or Charcoal/Pink for $21.99 with free shipping. That's the lowest total price we could find by $10. They're available in sizes 6 to 11, although not in all size/color combinations.