We have Bleak House here at MobileRead, as JSWolf mentioned, for free, if it is legally available in your area.
Here is a link to the thread with the epub version:
https://www.mobileread.com/forums/showthread.php?t=54054
Here is a link to the thread with the mobi version:
https://www.mobileread.com/forums/showthread.php?t=12763
I think both are the same version. It's a version with 40 illustrations. Not sure about the illustrations but per the thread it's a well-formatted version.