So I went to a children's clothing resale clearance sale with my sisters a couple of months ago. About four times a year this store has a huge clearance. They rent another retail space for the weekend, set up banquet tables and throw all the unsellable clothes out in huge piles. The public gets to dig through and try and find the gems. Every item of clothing sells for a quarter, so it's often worth your time if you have young kids. My kids are all too old to find much at these sales. My sister was shopping for a new baby on the way, and I was helping her find the cute girly stuff. We found several large bags of things for her and this for my middle girl:
Turning a dress into a skirt is a super simple switch. Most of the time you can retain the existing zipper or closure mechanism and a simple piece of elastic or tightening up the side seams will bring the waist in. It's a quick change that makes it easy to freshen up an old piece.
(I've turned an old dress into a skirt before with even better results. Check it out here: Old dress makeover)