This was a very big issue for us this year. We drove to Florida and I have younger kids that are growing FAST. I have also been ill this year and lost quite a bit of weight on none of my clothed fit. I was able to get way with baggy yoga pants up here for the Winter but before we left it was a real issue. I scrambled trying to borrow a couple of things from friends and in the end found that ordering clothes online was the best way to go.
I orderred heavuly from lands End and a great find, Heavenly Couture . I liked there whole T-shirt line- the basic green tee, basic black tee and my favourite , a cute pink pajama/short set.
All for under 25.00. They have an extensive junior clothing and every piece is 17.95- worth a look.