Walmart offers the Frozen Toddler Girl's Winter Boots for $13. Opt for in-store pickup to dodge the $4.97 shipping charge. That's $12 off list and the lowest price we could find. They're available in sizes 5 to 11.
Disney Store takes up to 50% off a selection of sale items. (Prices are as marked.) Shipping starts at $4.95, but orders of $75 or more qualify for free shipping via coupon code "SHIPMAGIC". A couple of best bets, each with $5.95 for shipping:
13 Deals offers the Disney Frozen Olaf Plush Backpack in White for $8.99 with free shipping. (Amazon has it for the same price with free shipping for Prime members.) That's $6 off list and the lowest total price we could find. It measures 15" x 8" x 5" and features adjustable shoulder straps and a small zip compartment.