Fairness compels me to say there may be an exception every 12th blue moon or so, but in the cluttered world of ebooks it is almost always true that you get what you pay for.
I’ve sampled a few free “books” out of curiosity. So far they’ve cost me nothing but time, obviously, but the benefits of getting a free work of fiction stop there.
A few hundred words do not a novel make.
Free or not, poor writing and editing do not increase a reader’s interest in suffering through more by the same author.
The time you spend reading crap is gone forever.
Don’t bother asking for a refund.