It's probably the washable marker stuff and will wash out. Or follow the advice given by previous posters.
My two cents: buy her clothes at thrift stores. Frisco has a nice one (Good will? not too far from I-75) In Plano there is a very nice Salvation Army at Spring Creek Parkway and Ave K (just east of I-75), an okay Good Will at Spring Creek and Alma (about a mile or so west of 75). For clothes that are even less expensive, there is The Thrift Store at 18th and Ave K.
Set yourself free from the Buy New mentality! My teenage daughter loves shopping thrift stores!
PS There are probably families at your church that would love to give you their outgrown clothes if you make your need known.