Buying IPs with poor reputation

[Ross Tajvar <ross () tajvar io>]

I'm curious if anyone has experience deliberately buying blacklisted
blocks, or blocks that otherwise have poor reputation. Is there a
significant price difference? How do you seek them out? Most of the sellers
I've found seem to focus on blocks with good reputation, or on improving
the reputation of a bad block. But I am interested in purchasing some IPs
for internal services where reputation doesn't really matter.

Thanks,
Ross