cant say what it's worth but my fomr always has 85h mechs on him since they open up a lot of combo kills on enemies that he otherwise wouldn't be able to H2 let alone S3 with charge vulcs.
Well, lacking a sacrificial special I don't see them having much market value outside of personal use like cameron stated above. That being said — 85h is so rare that you might be likely to find someone still interested; perhaps around 5-10 PDs is my estimate.
Using these on multiple characters for Frozen Deldepths (over a lower sac mechgun) would work great since they don't need the special to be killed. Lower enough HP to NHH or even NNH. And high enough EVP to sometimes be a bother
I used to carry an 80h vulcan extra for this purpose (until I got a beserk high hit).