I've seen one post of someone mentioning guys selling/giving away gear on Tumblr. I'm not familiar with Tumblr much, but is there anywhere else people are selling these items?

There is a yahoo group called FTM Buy and Sell, as well as a forum called Trans* Talk, which has a sales section to it. FTMgaragesale is also another big place where things are sold.
links-
http://groups.yahoo.com/group/ftmbuyandsell/
http://transtalk.yuku.com
http://ftmgaragesale.livejournal.com