Once thredUP receives and processes your returned bag, the credit can either be used to shop for more kid clothes on their site (online consignment shop) or transferred into your PayPal! They also have a fundraising option, which could be an awesome, new way for you to raise money for a given cause.
If this is your first time shopping with thredUP, you can click this link to get $10 off your first order! I plan on sending them more of my kids' outgrown clothes soon!
P.S. They accept sizes 12M and up.
If you have any questions, feel free to shoot them my way or check out their "how it works" page here.