I just bought a huge lot of Sanyo Oscon 470uf 6v SV series (Surface mount) capacitors. As many of you already know, these are very unique caps with low esr.
$1.75 ea
I would also consider trades for some Black gate caps
(3300uf 16v, 100uf 50v, 470uf 25v 470uf 50v and various others)