If you're handy you can also make your own pretty easily: in classic form, they are just a ribbon motor and transformer. (I use mine in conjunction with a cloudlifter.)
I made my own ribbon motor (which I don't recommend unless you're really wanting to geek out) but you can order the motors (and also entire kits) from
here or
here. I would think that price/value of those kits would be great, but I can't attest personally. My home-made mic is awesome... rolls of the highs a little, and not the lowest-noise mic, but easy to EQ.
(Pics of my mic
here and
here.)