UPDATE: If you spend $40 or more, use coupon code FREE40 to get FREE shipping.
BuyCostumes.com has some awesome clearance deals! Justgo here, click on the red sale tab (upper right), scroll down and click on the sale items you’d like to browse through. Make sure to browse low price to high price! There are quite few kids costumes priced $4.99 to $5.99, down from the regular cost of $30 to $50! Shipping starts at $4.99