So this might seem like an odd thing to sell secondhand but it really would be a good deal for someone. We are selling used reusable cloth baby diapers. They worked excellently for us and saved us a ton of money on diapers over the last two years. We have two different types:

21 Bumgenius Diapers (plus a few extra liners): They sell new for $17.95/ea, we are asking $5/ea. (http://www.cottonbabies.com/product_info.php?cPath=98&products_id=2424)

4 Grobaby Diapers (w/ 7 extra liners): They sell new for about $16-20/ea, we are asking $5/ea. (http://www.bumritediapers.com/GroVia_Hybrid_Diapering_System_s/112.htm)

All of the diapers have been washed and sanitized. They work great and are not that difficult (or gross) to take care of.

25 diapers is about the right amount to have from our experience. So we would be happy to sell all of them to a single family.