All children out grow clothing; its a fact of life. The constant re- supply is always so expensive and sometimes they hardly wear the new clothes and their on to the next size.
Well, my mother found a place that buys used kids clothes; if not in bad condition. You can check your area and locate a second hand store near you, but depending on condition you can make some great extra cash for that next round of clothes.
And remember, if you don't want to sell them please dont through clothes away. There are so many shelters that would love to have them.