At ThinkGeek, buy any one item and get one item for 50% off via coupon code "HEARTMOM". Shipping starts around $6, or spend $75 or more to qualify for free shipping. Deal ends April 24. A couple best bets with prices after coupon:
Journeys offers the UGG Women's Fluff Flip Flop Slippers in Gray for $39.99 with free shipping. That's tied with our February mention and the lowest total price we could find by $11. They're available in sizes 5 to 9.