5 old reverb tanks for $25. I haven't contacted the seller, so I don't know if they work. I've never messed with a real spring reverb before and don't know much about them. It would be fun to build a standalone reverb though.
http://portland.craigslist.org/mlt/msg/4561298656.html
http://portland.craigslist.org/mlt/msg/4561298656.html