Very, very, very low. I've never had to ask for refunds until I bought some things from Pakt that were merely repackaged docs from man pages nearly.
Repackaged man pages almost sounds surprisingly high quality for Packt. I've only encountered their content on O'Reilly's learning platform, so I've been lucky enough not to pay for any of it directly, but at this point I've been disappointed enough times that I just don't bother looking at anything they publish.
You can write your name without errors most of the time