thredUP is a kids clothing swap site. Browse their list of thousands of boxes full of preloved kids clothes & toys. Find one you want and pay $5 + $10.95 USPS shipping. Get your box delivered to your doorstep in just a couple of days. $5 fee is waived on your first purchase. You only pay for shipping.
You can also post your own box of preloved clothes/toys your child no longer wears on thredUP. When another member picks your box, send it 100% free of charge. They provide boxes, postage, and even schedule the pick-up.