I usually get mine through homeschoolclassifieds.com. Some people recommend vegsource.com too, but I find it extremely unorganized. It is an option though if you're willing to spend a lot if time searching. Haha
Depending on what you're looking for, there may be special groups too (yahoo, facebook). I use MFW and there is a yahoo group for that that's pretty active. The fb one is kind of sucky though. Lol
Wifey to Eric
, Mommy to Logan
I love TRADES!