If you have the time and a little patience, I would suggest trying to sell them online...you'll get more money back this way. I've sold clothes to the kids stores in the past, and you basically get nothing in return. Here are some of the places that I've used online:
1. www.classifiedomaha.com - I've sold many items through this site, more than just my kids clothes too! I would say this would be the easist route, because you can just connect with someone locally and then set a time/place to meet with them to make the exchange. The other sites below, you will have to mail the items out.
2. www.gently-used.com - this is just for kids items and I've sold a good amount through this site too.
3. www.babyloot.com - I've sold a few items through here, but not a big fan of the site.
4. www.mykidscloset.com - I haven't used this site for too long, but have sold a couple of items so far. This site also offers an affiliate program (if interested, let me know and I can provide you my link).
5. www.livedeal.com - Last one...with this site you can sell locally or nationally. I've used it alot in the past, mainly for other items though.
Like I said, you will need some time and patience to set it up and then wait for a buyer, but if you want to get a better return for your items this is what I suggest. If you have any questions, please feel free to ask.