A best bet is the Nine West Women's Pitcrew Sandals in four colors (White pictured) for $69.99 before the in-cart discount, $48.99 after. With free shipping, that's the lowest total price we could find by $21. They're available in sizes 5 to 12, although not in all size/color combinations.
Gotta have 'em by Mother's Day? Choose UPS Next Business Day delivery for a whopping $30. (We think your Mom can be patient, though — she waited nine months to have you, didn't she?)