Ebay is probably your best bet. Not sure how many eyes would see your decks if you posted them here - though I might be interested in a couple of the decks you just posted.
As for value, a lot depends on how quickly you want to sell them. You can do an auction and hope that a couple of interested folks show up and bid up the price, or you can do a buy it now and be prepared to wait. I just sold a Kalamazoo Aristocrat deck on eBay that I was posted for at least 6 months.
You can always check the sold listings on ebay to get an idea of what your decks might be worth, too.