Echoing what others have said, I'm sad to see you have to let it go. I read every post on your build log and it was certainly inspiring.
BaT or eBay are good options. Please don't take this as a slight to your car, because it isn't, but I don't think BaT will get you $25-30. Most of the cars there seem to be in the teens, with this 73 (http://bringatrailer.com/listing/1973-datsun-240z-14/) that went for almost $28 being an outlier. Of course, with auctions, what matters most is getting at least two people who really want the car, but that's never a guarantee. Good luck!