Wayfair offers the CommClad 18" 2-Drawer Mobile File Cabinet
in Black, model no. 27983, for
with free shipping.
(Overstock charges pennies more.)
That's the lowest total price we could find by $5. This letter-size file cabinet features glide drawer rails, privacy lock, and a caster kit.
Update: Wayfair's price has since dropped to $58.65 with free shipping.