Buying and selling my childrens clothes on eBay saves me a fortune!  Girls Gymboree clothes are truely the best as far as I am concerned.  They retain their value, provided you care for them properly and buy matching outfits & accessories.  Selling the clothes as an outfit will usually fetch more money than selling all of your size 2T stuff in one big lot.  Gymboree has a name for every line of clothing they sell.  If you know what the name of the line is, you will get much more for your money.  You can find current lines on their website: www.gymboree.com sign up for their emails...they send great coupons and have great specials like Gymbucks and Friends and Family.  Gymbucks can really save you a ton.  If you buy your clothes new from Gymboree...make sure it is Gymbucks time and that you buy as much as you can for the next year so it will all be on sale anyways!  I have also found a website that can help identify prior lines all the way back to 2000!  It has been extremely helpful to me:  www.gymbohaven.com and I think the person who runs it also sells on eBay.  When buying used Gymboree clothes on eBay you can tell the year the clothes were produced just by looking at the tag if visible in the pictures...the old tags have a big green & orange lower case G (prior to 2001), then they switched to a white tag with "gymboree" in pink(2001-2004) and now the tag is a peachy colored tag with white letters(2004-now).  Lots of old lines coordinate with current lines, too.  I buy a lot of clothes that can mix easily with older lines.  For example: Some items from the Tropical paridise line from last summer had a lot of oranges and reds which matches nicely with the La Playa line from 2 years prior.  or Dandelion Wishes and Sporting Green...basically the same color palette.  Good Luck!