Just in time for Halloween, thredUP is offering new members $4 off their first thredUP box! This means moms who haven't yet swapped on thredUP can get a box of gently-used costumes, clothing and more for only $1 plus flat-rate shipping. This offer is valid September 20th through September 21st. Use promo code "costumes" at check-out to claim a box of gently-used goods listed by another thredUP mom in the US.