It's available on Amazon and one of their "vendors" is selling it new for $12.48 plus shipping.
I am afraid with material of this nature, you sometimes have to just buy the thing if you want to see it. Unless you live in a city like Boston or San Francisco where you may be able to find it in some of the few some independent rental stores left out there (a dying breed, sadly).
FYI, I think the DVD release of this movie may be from a public domain print and thus not very good quality. Something was posted here about it last y ear when it came out. Check Seizure in the search engine on the site.
cheers, G.
