Use Crocs coupon code EXTRA10 during checkout.
Crocs has these Women's Patricia II Wedge Sandals on sale for $29.99. Use the coupon code for an extra 10%, dropping the price to $26.99. Use coupon code AUGFS to get free shipping. The same sandals sell for $33.99 at Zappos.
The Crocs eBay store has a selection of more than 30 kids and adult crocs on sale up to 60% off with free shipping. Colors and sizes are limited so order them quickly if they are available in your size.