Save Money on Kids Items with thredUP

I just heard of a site where you can trade your gently used clothes and toys that no longer fit your child for a box of new to you items that do.  The website is called thredUP.  If you decide to use their service your first box is FREE, just pay shipping cost.  If you continue to use thredUP, each box of clothes is then only $5 plus the cost of shipping.    The boxes are not just for younger kids.  They have sizes for my 12 yr old son and 10 yr old daughter.  I know now where I am going to check first the next time they have a huge growth spurt.